10 for the Road: Essential Nutrients for Endurance Athletes
August 12, 2009
Filed under Crossfit, Diet And Nutrition, Running, Triathlon
By Alan Christianson, N.D
Quite simply, athletes need more nutrients than less-active people. They demand more from their bodies than even average fitness buffs and so must compensate with the right nutrients from foods or supplements to keep performance—and recovery—at its peak.
The more intense the exercise or sport, the greater the body's nutrient needs. Athletes who participate in endurance sports—those that involve more than one hour of consistent activity—have specific needs because of what they demand from their bodies. For example, athletes lose more electrolytes, such as magnesium, potassium and sodium, through perspiration and must diligently replace them. The wear and tear of intense activity may necessitate increased intake of antioxidants such as vitamin E, which can help protect muscle cells from oxidative damage. Since muscle-tissue breakdown is common during intense exercise, athletes also need more proteins to repair the tissues.
To keep their bodies performing optimally, endurance athletes should be familiar with these 10 important nutrients.
The first seven essential supplements are the minerals calcium, iron, magnesium, potassium, selenium, sodium and zinc. Their benefits range from keeping bones strong to minimizing fatigue.
- CALCIUM This may be the most important nutrient for an athlete. In a survey of more than 10,000 male and female athletes ages 7 to 50, fewer than half consumed 1,000 mg of calcium daily.1 The recommended dietary intake ranges from 1,000 to 1,500 mg/day depending on age and gender.
For female athletes, calcium intake is of particular concern. Excessive training—more than seven hours per week—may cause hormonal declines in young girls that can stop menstruation. This hormonal decline also compromises bone formation, possibly leading to premature, irreversible osteoporosis.2 Recent research shows that male endurance athletes of all ages experience testosterone deficits that also can cause osteoporosis.3
Athletes should monitor their calcium intake. Dairy foods can supply the required amounts unless sensitivities exclude them from the diet. But a diet without dairy foods requires supplements. All athletes should make sure they get 1,200 to 1,500 mg of calcium daily from food or supplements. Drinking a cup of skim milk, for example, provides about 300 mg of calcium.
- IRON For the casual athlete who trains less than four hours per week, iron deficiency is no more of a concern than for a sedentary person. But athletes who train for six or more hours per week often have iron-deficiency anemia and should be checked yearly for the condition. Female athletes who are unable to correct such mild anemia through diet can benefit from supplements.4
(26.2 miles)
Triathlons
(swim, bike, run)
Ultramarathons
(50 or 100 miles) Athletes use iron stores more quickly than nonathletes and, considering the neurologic effects of anemia on children and teens who engage in rigorous sports, adequate intake of iron is quite important.5 The recommended dietary allowance (RDA) for iron ranges from 10 to 15 mg/day—an amount easily acquired from food. In the absence of anemia, athletes shouldn't take any supplemental iron because it raises the risk of heart disease and colon cancer.
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Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes' diets are usually low in magnesium, generally leads to the need for supplementation.7 Recommended intake for endurance athletes is 500 to 800 mg daily.8 Higher doses can cause diarrhea.
In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss was estimated at 435 mg/hour. The rate of potassium loss is approximately 200 mg/kg of weight lost during exercise.9 Cells release potassium into the bloodstream and serum levels rise with exercise, possibly instigating fatigue. Potassium supplementation after short events (less than two hours), and during and after long events, is warranted.10 For postactivity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes. Supplement potassium cautiously because too much too quickly can cause cardiac arrest. Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.10
Research shows selenium benefits athletes' immune function and helps repair cellular damage. Researchers studied the selenium supplementation effects on muscle SeGPx in 24 healthy nonsmoking males. Half took 240 mcg of sodium selenite; half took placebo. After cycling to exhaustion—durations ranged from 2.6 to 3.5 hours—the group that took selenium showed less cellular damage.12 Supplementation with 200 mcg of selenium is safe and warranted for endurance athletes.13
A prospective study was performed on 36 athletes during a three- to four-hour triathlon and 64 athletes at an ironman race, which lasts between nine and 15 hours. No athletes were hyponatremic after the shorter race, but 27 percent were hyponatremic following the ironman. An average of 17 percent of the ironman participants required medical attention, most for hyponatremia.14 Extrapolated from that study, athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage and 100 to 300 mg sodium per hour from other sources.
Those who train without days off lose zinc even more quickly. In a study of cyclists, researchers looked at zinc excretion via sweat. Half of the group underwent intense training for two months. Half underwent moderate training with two to three days off per week. Both groups were studied before and after. The exercising group showed increased zinc excretion while the control group showed no increase.16 The researchers believe altered zinc metabolism coupled with increased zinc excretion and stress levels lead to fatigue and decreased endurance. Athletes should take 30 to 60 mg zinc daily.17 Zinc picolinate or monomethionate are most easily tolerated.18 Prevent Oxidative Damage
In a study of 30 top-class cyclists, five months of supplementation with natural vitamin E (alpha-tocopherol) at an 800-IU daily dose significantly decreased markers of oxidative damage to muscle tissue. However, vitamin E did not benefit athletic performance. Studies evaluating vitamin E as an ergogenic, or performance aid, show no benefit.19 One possible exception is at higher altitudes where oxidative stress is more intense. A group of six mountain climbers took 400 mg synthetic vitamin E (dl-alpha-tocopherol acetate). During exertion at altitude, they showed less output of pentane and lactic acid—both markers of oxidative damage, but not suggestive of improved athletic performance. The athletes also showed a statistically significant increase in anaerobic threshold compared to a placebo group.20 The amount of vitamin E necessary to benefit athletes is not obtainable through diet. The jury is still out on natural vs. synthetic vitamin E, but endurance athletes should take 400 to 800 IU/day. Protein and Glutamine
Endurance athletes need more protein for different reasons than strength athletes do. Endurance athletes primarily use protein for maintaining aerobic metabolism, compared with the increased tissue-repair needs of strength athletes. When intake is inadequate, the body sequesters the needed proteins from lean tissue, which gives overtrained endurance athletes a gaunt appearance. A protein deficit also impairs an athlete's recovery and wound-healing ability.14 Researchers recommend endurance athletes eat 1.2 to 1.4 g/kg of body weight/day of protein.22 For a 155-pound athlete, this means a total of 85 to 100 g protein per day. Only a few studies recommend protein intake levels as high as 2 g/kg of body weight/day.23
Oral glutamine replacement after exercise can lower infection risk. In one study, 200 runners and rowers were given placebo or 2,000 mg glutamine two hours after exercise. In the seven days following the exercise, 81 percent of the glutamine-supplemented group were infection-free compared to 49 percent in the placebo group.26 A supplement that provides 2 g glutamine daily is a wise choice for athletes in training.26 Athletes who train strenuously for competition have greater nutritional needs than sedentary people. Adequate nutrients can mean quicker recovery time, lower infection rates, less fatigue, and ultimately, can help athletes reach their desired performance levels.
References 1. Guezennec CY, et al. Is there a relationship between physical activity and dietary calcium intake? A survey in 10,373 young French subjects. Med Sci Sports Exerc 1998 May;30(5):732-9. 2. Voss LA, et al. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg 1998 Nov-Dec;6(6):349-57. 3. Bennell KL, et al. Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes. Br J Sports Med 1996 Sep;30(3):205-8. 4. Eichner ER. Sports anemia, iron supplements, and blood doping. Med Sci Sports Exerc 1992 Sep;24(9 Suppl):S315-8. 5. Weaver CM, et al. Exercise and iron status. J Nutr 1992 Mar;122(3 Suppl):782-7. 6. Altura BM, et al. Magnesium depletion impairs myocardial carbohydrate and lipid metabolism and cardiac bioenergetics and raises myocardial calcium content in-vivo: relationship to etiology of cardiac diseases. Biochem Mol Biol Int 1996 Dec;40(6):1183-90. 7. Lukaski HC, et al. Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Int J Sport Nutr, 1995;5 Suppl:S74-83. 8. Seelig M. Magnesium deficiency in the pathogenesis of disease. New York: Plenum Press; 1980. 9. Wenk C, et al. Methodological studies of the estimation of loss of sodium, potassium, calcium and magnesium through the skin during a 10 km run. Z Ernahrungswiss 1993 Dec;(4):301-7. 10. Tarnopolsky MA, et al. Mixed carbohydrate supplementation increases carbohydrate oxidation and endurance exercise performance and attenuates potassium accumulation. Int J Sport Nutr 1996 Dec;(4):323-36. 11. Venditti P. Effect of training on antioxidant capacity, tissue damage, and endurance of adult male rats. Int J Sports Med 1997 Oct;18(7):497-502. 12. Tessier F, et al. Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation. Biol Trace Elem Res, 1995 Jan-Mar;47(1-3):279-85. 13. Persson-Moschos M, et al. Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium. Eur J Clin Nutr 1998 May;52(5):363-7. 14. Hiller WD, et al. Medical and physiological considerations in triathlons. Am J Sports Med 1987 Mar;(2):164-7. 15. Cordova A. Behaviour of zinc in physical exercise: a special reference to immunity and fatigue. Neurosci Biobehav Rev 1995 Fall;19(3):439-45. 16. Cordova A, et al. Effect of training on zinc metabolism: changes in serum and sweat zinc concentrations in sportsmen. Ann Nutr Metab 1998;42(5):274-82. 17. Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-8. 18. Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 19. Rokitzki L, et al. Alpha-tocopherol supplementation in racing cyclists during extreme endurance training. Int J Sport Nutr 1994 Sep;4(3):253-64. 20. Simon-Schnass I, et al. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58(1):49-54. 21. Lemon PW, et al. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995 Jun;5 Suppl:S39-61. 22. Shephard, RJ, et al. Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 1998;4:22-48. 23. Rohde T, et al. The immune system and serum glutamine during a triathlon. Eur J Appl Physiol 1996;74(5):428-34. 24. Newsholme EA, et al. The proposed role of glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition 1997 Jul-Aug; 13(7-8):728-30. 25.Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 26.Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73(5):488-90.
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Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes' diets are usually low in magnesium, generally leads to the need for supplementation.7 Recommended intake for endurance athletes is 500 to 800 mg daily.8 Higher doses can cause diarrhea.
In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss was estimated at 435 mg/hour. The rate of potassium loss is approximately 200 mg/kg of weight lost during exercise.9 Cells release potassium into the bloodstream and serum levels rise with exercise, possibly instigating fatigue. Potassium supplementation after short events (less than two hours), and during and after long events, is warranted.10 For postactivity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes. Supplement potassium cautiously because too much too quickly can cause cardiac arrest. Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.10
Research shows selenium benefits athletes' immune function and helps repair cellular damage. Researchers studied the selenium supplementation effects on muscle SeGPx in 24 healthy nonsmoking males. Half took 240 mcg of sodium selenite; half took placebo. After cycling to exhaustion—durations ranged from 2.6 to 3.5 hours—the group that took selenium showed less cellular damage.12 Supplementation with 200 mcg of selenium is safe and warranted for endurance athletes.13
A prospective study was performed on 36 athletes during a three- to four-hour triathlon and 64 athletes at an ironman race, which lasts between nine and 15 hours. No athletes were hyponatremic after the shorter race, but 27 percent were hyponatremic following the ironman. An average of 17 percent of the ironman participants required medical attention, most for hyponatremia.14 Extrapolated from that study, athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage and 100 to 300 mg sodium per hour from other sources.
Those who train without days off lose zinc even more quickly. In a study of cyclists, researchers looked at zinc excretion via sweat. Half of the group underwent intense training for two months. Half underwent moderate training with two to three days off per week. Both groups were studied before and after. The exercising group showed increased zinc excretion while the control group showed no increase.16 The researchers believe altered zinc metabolism coupled with increased zinc excretion and stress levels lead to fatigue and decreased endurance. Athletes should take 30 to 60 mg zinc daily.17 Zinc picolinate or monomethionate are most easily tolerated.18 Prevent Oxidative Damage
In a study of 30 top-class cyclists, five months of supplementation with natural vitamin E (alpha-tocopherol) at an 800-IU daily dose significantly decreased markers of oxidative damage to muscle tissue. However, vitamin E did not benefit athletic performance. Studies evaluating vitamin E as an ergogenic, or performance aid, show no benefit.19 One possible exception is at higher altitudes where oxidative stress is more intense. A group of six mountain climbers took 400 mg synthetic vitamin E (dl-alpha-tocopherol acetate). During exertion at altitude, they showed less output of pentane and lactic acid—both markers of oxidative damage, but not suggestive of improved athletic performance. The athletes also showed a statistically significant increase in anaerobic threshold compared to a placebo group.20 The amount of vitamin E necessary to benefit athletes is not obtainable through diet. The jury is still out on natural vs. synthetic vitamin E, but endurance athletes should take 400 to 800 IU/day. Protein and Glutamine
Endurance athletes need more protein for different reasons than strength athletes do. Endurance athletes primarily use protein for maintaining aerobic metabolism, compared with the increased tissue-repair needs of strength athletes. When intake is inadequate, the body sequesters the needed proteins from lean tissue, which gives overtrained endurance athletes a gaunt appearance. A protein deficit also impairs an athlete's recovery and wound-healing ability.14 Researchers recommend endurance athletes eat 1.2 to 1.4 g/kg of body weight/day of protein.22 For a 155-pound athlete, this means a total of 85 to 100 g protein per day. Only a few studies recommend protein intake levels as high as 2 g/kg of body weight/day.23
Oral glutamine replacement after exercise can lower infection risk. In one study, 200 runners and rowers were given placebo or 2,000 mg glutamine two hours after exercise. In the seven days following the exercise, 81 percent of the glutamine-supplemented group were infection-free compared to 49 percent in the placebo group.26 A supplement that provides 2 g glutamine daily is a wise choice for athletes in training.26 Athletes who train strenuously for competition have greater nutritional needs than sedentary people. Adequate nutrients can mean quicker recovery time, lower infection rates, less fatigue, and ultimately, can help athletes reach their desired performance levels.
References 1. Guezennec CY, et al. Is there a relationship between physical activity and dietary calcium intake? A survey in 10,373 young French subjects. Med Sci Sports Exerc 1998 May;30(5):732-9. 2. Voss LA, et al. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg 1998 Nov-Dec;6(6):349-57. 3. Bennell KL, et al. Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes. Br J Sports Med 1996 Sep;30(3):205-8. 4. Eichner ER. Sports anemia, iron supplements, and blood doping. Med Sci Sports Exerc 1992 Sep;24(9 Suppl):S315-8. 5. Weaver CM, et al. Exercise and iron status. J Nutr 1992 Mar;122(3 Suppl):782-7. 6. Altura BM, et al. Magnesium depletion impairs myocardial carbohydrate and lipid metabolism and cardiac bioenergetics and raises myocardial calcium content in-vivo: relationship to etiology of cardiac diseases. Biochem Mol Biol Int 1996 Dec;40(6):1183-90. 7. Lukaski HC, et al. Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Int J Sport Nutr, 1995;5 Suppl:S74-83. 8. Seelig M. Magnesium deficiency in the pathogenesis of disease. New York: Plenum Press; 1980. 9. Wenk C, et al. Methodological studies of the estimation of loss of sodium, potassium, calcium and magnesium through the skin during a 10 km run. Z Ernahrungswiss 1993 Dec;(4):301-7. 10. Tarnopolsky MA, et al. Mixed carbohydrate supplementation increases carbohydrate oxidation and endurance exercise performance and attenuates potassium accumulation. Int J Sport Nutr 1996 Dec;(4):323-36. 11. Venditti P. Effect of training on antioxidant capacity, tissue damage, and endurance of adult male rats. Int J Sports Med 1997 Oct;18(7):497-502. 12. Tessier F, et al. Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation. Biol Trace Elem Res, 1995 Jan-Mar;47(1-3):279-85. 13. Persson-Moschos M, et al. Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium. Eur J Clin Nutr 1998 May;52(5):363-7. 14. Hiller WD, et al. Medical and physiological considerations in triathlons. Am J Sports Med 1987 Mar;(2):164-7. 15. Cordova A. Behaviour of zinc in physical exercise: a special reference to immunity and fatigue. Neurosci Biobehav Rev 1995 Fall;19(3):439-45. 16. Cordova A, et al. Effect of training on zinc metabolism: changes in serum and sweat zinc concentrations in sportsmen. Ann Nutr Metab 1998;42(5):274-82. 17. Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-8. 18. Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 19. Rokitzki L, et al. Alpha-tocopherol supplementation in racing cyclists during extreme endurance training. Int J Sport Nutr 1994 Sep;4(3):253-64. 20. Simon-Schnass I, et al. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58(1):49-54. 21. Lemon PW, et al. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995 Jun;5 Suppl:S39-61. 22. Shephard, RJ, et al. Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 1998;4:22-48. 23. Rohde T, et al. The immune system and serum glutamine during a triathlon. Eur J Appl Physiol 1996;74(5):428-34. 24. Newsholme EA, et al. The proposed role of glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition 1997 Jul-Aug; 13(7-8):728-30. 25.Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 26.Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73(5):488-90.
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Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes' diets are usually low in magnesium, generally leads to the need for supplementation.7 Recommended intake for endurance athletes is 500 to 800 mg daily.8 Higher doses can cause diarrhea.
In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss was estimated at 435 mg/hour. The rate of potassium loss is approximately 200 mg/kg of weight lost during exercise.9 Cells release potassium into the bloodstream and serum levels rise with exercise, possibly instigating fatigue. Potassium supplementation after short events (less than two hours), and during and after long events, is warranted.10 For postactivity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes. Supplement potassium cautiously because too much too quickly can cause cardiac arrest. Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.10
Research shows selenium benefits athletes' immune function and helps repair cellular damage. Researchers studied the selenium supplementation effects on muscle SeGPx in 24 healthy nonsmoking males. Half took 240 mcg of sodium selenite; half took placebo. After cycling to exhaustion—durations ranged from 2.6 to 3.5 hours—the group that took selenium showed less cellular damage.12 Supplementation with 200 mcg of selenium is safe and warranted for endurance athletes.13
A prospective study was performed on 36 athletes during a three- to four-hour triathlon and 64 athletes at an ironman race, which lasts between nine and 15 hours. No athletes were hyponatremic after the shorter race, but 27 percent were hyponatremic following the ironman. An average of 17 percent of the ironman participants required medical attention, most for hyponatremia.14 Extrapolated from that study, athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage and 100 to 300 mg sodium per hour from other sources.
Those who train without days off lose zinc even more quickly. In a study of cyclists, researchers looked at zinc excretion via sweat. Half of the group underwent intense training for two months. Half underwent moderate training with two to three days off per week. Both groups were studied before and after. The exercising group showed increased zinc excretion while the control group showed no increase.16 The researchers believe altered zinc metabolism coupled with increased zinc excretion and stress levels lead to fatigue and decreased endurance. Athletes should take 30 to 60 mg zinc daily.17 Zinc picolinate or monomethionate are most easily tolerated.18 Prevent Oxidative Damage
In a study of 30 top-class cyclists, five months of supplementation with natural vitamin E (alpha-tocopherol) at an 800-IU daily dose significantly decreased markers of oxidative damage to muscle tissue. However, vitamin E did not benefit athletic performance. Studies evaluating vitamin E as an ergogenic, or performance aid, show no benefit.19 One possible exception is at higher altitudes where oxidative stress is more intense. A group of six mountain climbers took 400 mg synthetic vitamin E (dl-alpha-tocopherol acetate). During exertion at altitude, they showed less output of pentane and lactic acid—both markers of oxidative damage, but not suggestive of improved athletic performance. The athletes also showed a statistically significant increase in anaerobic threshold compared to a placebo group.20 The amount of vitamin E necessary to benefit athletes is not obtainable through diet. The jury is still out on natural vs. synthetic vitamin E, but endurance athletes should take 400 to 800 IU/day. Protein and Glutamine
Endurance athletes need more protein for different reasons than strength athletes do. Endurance athletes primarily use protein for maintaining aerobic metabolism, compared with the increased tissue-repair needs of strength athletes. When intake is inadequate, the body sequesters the needed proteins from lean tissue, which gives overtrained endurance athletes a gaunt appearance. A protein deficit also impairs an athlete's recovery and wound-healing ability.14 Researchers recommend endurance athletes eat 1.2 to 1.4 g/kg of body weight/day of protein.22 For a 155-pound athlete, this means a total of 85 to 100 g protein per day. Only a few studies recommend protein intake levels as high as 2 g/kg of body weight/day.23
Oral glutamine replacement after exercise can lower infection risk. In one study, 200 runners and rowers were given placebo or 2,000 mg glutamine two hours after exercise. In the seven days following the exercise, 81 percent of the glutamine-supplemented group were infection-free compared to 49 percent in the placebo group.26 A supplement that provides 2 g glutamine daily is a wise choice for athletes in training.26 Athletes who train strenuously for competition have greater nutritional needs than sedentary people. Adequate nutrients can mean quicker recovery time, lower infection rates, less fatigue, and ultimately, can help athletes reach their desired performance levels.
References 1. Guezennec CY, et al. Is there a relationship between physical activity and dietary calcium intake? A survey in 10,373 young French subjects. Med Sci Sports Exerc 1998 May;30(5):732-9. 2. Voss LA, et al. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg 1998 Nov-Dec;6(6):349-57. 3. Bennell KL, et al. Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes. Br J Sports Med 1996 Sep;30(3):205-8. 4. Eichner ER. Sports anemia, iron supplements, and blood doping. Med Sci Sports Exerc 1992 Sep;24(9 Suppl):S315-8. 5. Weaver CM, et al. Exercise and iron status. J Nutr 1992 Mar;122(3 Suppl):782-7. 6. Altura BM, et al. Magnesium depletion impairs myocardial carbohydrate and lipid metabolism and cardiac bioenergetics and raises myocardial calcium content in-vivo: relationship to etiology of cardiac diseases. Biochem Mol Biol Int 1996 Dec;40(6):1183-90. 7. Lukaski HC, et al. Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Int J Sport Nutr, 1995;5 Suppl:S74-83. 8. Seelig M. Magnesium deficiency in the pathogenesis of disease. New York: Plenum Press; 1980. 9. Wenk C, et al. Methodological studies of the estimation of loss of sodium, potassium, calcium and magnesium through the skin during a 10 km run. Z Ernahrungswiss 1993 Dec;(4):301-7. 10. Tarnopolsky MA, et al. Mixed carbohydrate supplementation increases carbohydrate oxidation and endurance exercise performance and attenuates potassium accumulation. Int J Sport Nutr 1996 Dec;(4):323-36. 11. Venditti P. Effect of training on antioxidant capacity, tissue damage, and endurance of adult male rats. Int J Sports Med 1997 Oct;18(7):497-502. 12. Tessier F, et al. Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation. Biol Trace Elem Res, 1995 Jan-Mar;47(1-3):279-85. 13. Persson-Moschos M, et al. Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium. Eur J Clin Nutr 1998 May;52(5):363-7. 14. Hiller WD, et al. Medical and physiological considerations in triathlons. Am J Sports Med 1987 Mar;(2):164-7. 15. Cordova A. Behaviour of zinc in physical exercise: a special reference to immunity and fatigue. Neurosci Biobehav Rev 1995 Fall;19(3):439-45. 16. Cordova A, et al. Effect of training on zinc metabolism: changes in serum and sweat zinc concentrations in sportsmen. Ann Nutr Metab 1998;42(5):274-82. 17. Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-8. 18. Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 19. Rokitzki L, et al. Alpha-tocopherol supplementation in racing cyclists during extreme endurance training. Int J Sport Nutr 1994 Sep;4(3):253-64. 20. Simon-Schnass I, et al. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58(1):49-54. 21. Lemon PW, et al. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995 Jun;5 Suppl:S39-61. 22. Shephard, RJ, et al. Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 1998;4:22-48. 23. Rohde T, et al. The immune system and serum glutamine during a triathlon. Eur J Appl Physiol 1996;74(5):428-34. 24. Newsholme EA, et al. The proposed role of glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition 1997 Jul-Aug; 13(7-8):728-30. 25.Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 26.Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73(5):488-90.
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Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes' diets are usually low in magnesium, generally leads to the need for supplementation.7 Recommended intake for endurance athletes is 500 to 800 mg daily.8 Higher doses can cause diarrhea.
In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss was estimated at 435 mg/hour. The rate of potassium loss is approximately 200 mg/kg of weight lost during exercise.9 Cells release potassium into the bloodstream and serum levels rise with exercise, possibly instigating fatigue. Potassium supplementation after short events (less than two hours), and during and after long events, is warranted.10 For postactivity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes. Supplement potassium cautiously because too much too quickly can cause cardiac arrest. Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.10
Research shows selenium benefits athletes' immune function and helps repair cellular damage. Researchers studied the selenium supplementation effects on muscle SeGPx in 24 healthy nonsmoking males. Half took 240 mcg of sodium selenite; half took placebo. After cycling to exhaustion—durations ranged from 2.6 to 3.5 hours—the group that took selenium showed less cellular damage.12 Supplementation with 200 mcg of selenium is safe and warranted for endurance athletes.13
A prospective study was performed on 36 athletes during a three- to four-hour triathlon and 64 athletes at an ironman race, which lasts between nine and 15 hours. No athletes were hyponatremic after the shorter race, but 27 percent were hyponatremic following the ironman. An average of 17 percent of the ironman participants required medical attention, most for hyponatremia.14 Extrapolated from that study, athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage and 100 to 300 mg sodium per hour from other sources.
Those who train without days off lose zinc even more quickly. In a study of cyclists, researchers looked at zinc excretion via sweat. Half of the group underwent intense training for two months. Half underwent moderate training with two to three days off per week. Both groups were studied before and after. The exercising group showed increased zinc excretion while the control group showed no increase.16 The researchers believe altered zinc metabolism coupled with increased zinc excretion and stress levels lead to fatigue and decreased endurance. Athletes should take 30 to 60 mg zinc daily.17 Zinc picolinate or monomethionate are most easily tolerated.18 Prevent Oxidative Damage
In a study of 30 top-class cyclists, five months of supplementation with natural vitamin E (alpha-tocopherol) at an 800-IU daily dose significantly decreased markers of oxidative damage to muscle tissue. However, vitamin E did not benefit athletic performance. Studies evaluating vitamin E as an ergogenic, or performance aid, show no benefit.19 One possible exception is at higher altitudes where oxidative stress is more intense. A group of six mountain climbers took 400 mg synthetic vitamin E (dl-alpha-tocopherol acetate). During exertion at altitude, they showed less output of pentane and lactic acid—both markers of oxidative damage, but not suggestive of improved athletic performance. The athletes also showed a statistically significant increase in anaerobic threshold compared to a placebo group.20 The amount of vitamin E necessary to benefit athletes is not obtainable through diet. The jury is still out on natural vs. synthetic vitamin E, but endurance athletes should take 400 to 800 IU/day. Protein and Glutamine
Endurance athletes need more protein for different reasons than strength athletes do. Endurance athletes primarily use protein for maintaining aerobic metabolism, compared with the increased tissue-repair needs of strength athletes. When intake is inadequate, the body sequesters the needed proteins from lean tissue, which gives overtrained endurance athletes a gaunt appearance. A protein deficit also impairs an athlete's recovery and wound-healing ability.14 Researchers recommend endurance athletes eat 1.2 to 1.4 g/kg of body weight/day of protein.22 For a 155-pound athlete, this means a total of 85 to 100 g protein per day. Only a few studies recommend protein intake levels as high as 2 g/kg of body weight/day.23
Oral glutamine replacement after exercise can lower infection risk. In one study, 200 runners and rowers were given placebo or 2,000 mg glutamine two hours after exercise. In the seven days following the exercise, 81 percent of the glutamine-supplemented group were infection-free compared to 49 percent in the placebo group.26 A supplement that provides 2 g glutamine daily is a wise choice for athletes in training.26 Athletes who train strenuously for competition have greater nutritional needs than sedentary people. Adequate nutrients can mean quicker recovery time, lower infection rates, less fatigue, and ultimately, can help athletes reach their desired performance levels.
References 1. Guezennec CY, et al. Is there a relationship between physical activity and dietary calcium intake? A survey in 10,373 young French subjects. Med Sci Sports Exerc 1998 May;30(5):732-9. 2. Voss LA, et al. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg 1998 Nov-Dec;6(6):349-57. 3. Bennell KL, et al. Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes. Br J Sports Med 1996 Sep;30(3):205-8. 4. Eichner ER. Sports anemia, iron supplements, and blood doping. Med Sci Sports Exerc 1992 Sep;24(9 Suppl):S315-8. 5. Weaver CM, et al. Exercise and iron status. J Nutr 1992 Mar;122(3 Suppl):782-7. 6. Altura BM, et al. Magnesium depletion impairs myocardial carbohydrate and lipid metabolism and cardiac bioenergetics and raises myocardial calcium content in-vivo: relationship to etiology of cardiac diseases. Biochem Mol Biol Int 1996 Dec;40(6):1183-90. 7. Lukaski HC, et al. Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Int J Sport Nutr, 1995;5 Suppl:S74-83. 8. Seelig M. Magnesium deficiency in the pathogenesis of disease. New York: Plenum Press; 1980. 9. Wenk C, et al. Methodological studies of the estimation of loss of sodium, potassium, calcium and magnesium through the skin during a 10 km run. Z Ernahrungswiss 1993 Dec;(4):301-7. 10. Tarnopolsky MA, et al. Mixed carbohydrate supplementation increases carbohydrate oxidation and endurance exercise performance and attenuates potassium accumulation. Int J Sport Nutr 1996 Dec;(4):323-36. 11. Venditti P. Effect of training on antioxidant capacity, tissue damage, and endurance of adult male rats. Int J Sports Med 1997 Oct;18(7):497-502. 12. Tessier F, et al. Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation. Biol Trace Elem Res, 1995 Jan-Mar;47(1-3):279-85. 13. Persson-Moschos M, et al. Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium. Eur J Clin Nutr 1998 May;52(5):363-7. 14. Hiller WD, et al. Medical and physiological considerations in triathlons. Am J Sports Med 1987 Mar;(2):164-7. 15. Cordova A. Behaviour of zinc in physical exercise: a special reference to immunity and fatigue. Neurosci Biobehav Rev 1995 Fall;19(3):439-45. 16. Cordova A, et al. Effect of training on zinc metabolism: changes in serum and sweat zinc concentrations in sportsmen. Ann Nutr Metab 1998;42(5):274-82. 17. Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-8. 18. Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 19. Rokitzki L, et al. Alpha-tocopherol supplementation in racing cyclists during extreme endurance training. Int J Sport Nutr 1994 Sep;4(3):253-64. 20. Simon-Schnass I, et al. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58(1):49-54. 21. Lemon PW, et al. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995 Jun;5 Suppl:S39-61. 22. Shephard, RJ, et al. Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 1998;4:22-48. 23. Rohde T, et al. The immune system and serum glutamine during a triathlon. Eur J Appl Physiol 1996;74(5):428-34. 24. Newsholme EA, et al. The proposed role of glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition 1997 Jul-Aug; 13(7-8):728-30. 25.Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 26.Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73(5):488-90.
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Athletes lose magnesium through sweat and urine. This, combined with the fact that athletes' diets are usually low in magnesium, generally leads to the need for supplementation.7 Recommended intake for endurance athletes is 500 to 800 mg daily.8 Higher doses can cause diarrhea.
In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss was estimated at 435 mg/hour. The rate of potassium loss is approximately 200 mg/kg of weight lost during exercise.9 Cells release potassium into the bloodstream and serum levels rise with exercise, possibly instigating fatigue. Potassium supplementation after short events (less than two hours), and during and after long events, is warranted.10 For postactivity replacement, athletes should take about 435 mg/hour of exercise or 200 mg/kg of weight loss. As much as 150 mg/hour during activity can be tolerated by most athletes. Supplement potassium cautiously because too much too quickly can cause cardiac arrest. Supplementing with potassium during training does increase markers of recovery, primarily serum lactate and muscle hydration, but does not aid performance.10
Research shows selenium benefits athletes' immune function and helps repair cellular damage. Researchers studied the selenium supplementation effects on muscle SeGPx in 24 healthy nonsmoking males. Half took 240 mcg of sodium selenite; half took placebo. After cycling to exhaustion—durations ranged from 2.6 to 3.5 hours—the group that took selenium showed less cellular damage.12 Supplementation with 200 mcg of selenium is safe and warranted for endurance athletes.13
A prospective study was performed on 36 athletes during a three- to four-hour triathlon and 64 athletes at an ironman race, which lasts between nine and 15 hours. No athletes were hyponatremic after the shorter race, but 27 percent were hyponatremic following the ironman. An average of 17 percent of the ironman participants required medical attention, most for hyponatremia.14 Extrapolated from that study, athletes should aim for 80 to 100 mg sodium per quart of hydrating beverage and 100 to 300 mg sodium per hour from other sources.
Those who train without days off lose zinc even more quickly. In a study of cyclists, researchers looked at zinc excretion via sweat. Half of the group underwent intense training for two months. Half underwent moderate training with two to three days off per week. Both groups were studied before and after. The exercising group showed increased zinc excretion while the control group showed no increase.16 The researchers believe altered zinc metabolism coupled with increased zinc excretion and stress levels lead to fatigue and decreased endurance. Athletes should take 30 to 60 mg zinc daily.17 Zinc picolinate or monomethionate are most easily tolerated.18 Prevent Oxidative Damage
In a study of 30 top-class cyclists, five months of supplementation with natural vitamin E (alpha-tocopherol) at an 800-IU daily dose significantly decreased markers of oxidative damage to muscle tissue. However, vitamin E did not benefit athletic performance. Studies evaluating vitamin E as an ergogenic, or performance aid, show no benefit.19 One possible exception is at higher altitudes where oxidative stress is more intense. A group of six mountain climbers took 400 mg synthetic vitamin E (dl-alpha-tocopherol acetate). During exertion at altitude, they showed less output of pentane and lactic acid—both markers of oxidative damage, but not suggestive of improved athletic performance. The athletes also showed a statistically significant increase in anaerobic threshold compared to a placebo group.20 The amount of vitamin E necessary to benefit athletes is not obtainable through diet. The jury is still out on natural vs. synthetic vitamin E, but endurance athletes should take 400 to 800 IU/day. Protein and Glutamine
Endurance athletes need more protein for different reasons than strength athletes do. Endurance athletes primarily use protein for maintaining aerobic metabolism, compared with the increased tissue-repair needs of strength athletes. When intake is inadequate, the body sequesters the needed proteins from lean tissue, which gives overtrained endurance athletes a gaunt appearance. A protein deficit also impairs an athlete's recovery and wound-healing ability.14 Researchers recommend endurance athletes eat 1.2 to 1.4 g/kg of body weight/day of protein.22 For a 155-pound athlete, this means a total of 85 to 100 g protein per day. Only a few studies recommend protein intake levels as high as 2 g/kg of body weight/day.23
Oral glutamine replacement after exercise can lower infection risk. In one study, 200 runners and rowers were given placebo or 2,000 mg glutamine two hours after exercise. In the seven days following the exercise, 81 percent of the glutamine-supplemented group were infection-free compared to 49 percent in the placebo group.26 A supplement that provides 2 g glutamine daily is a wise choice for athletes in training.26 Athletes who train strenuously for competition have greater nutritional needs than sedentary people. Adequate nutrients can mean quicker recovery time, lower infection rates, less fatigue, and ultimately, can help athletes reach their desired performance levels.
References 1. Guezennec CY, et al. Is there a relationship between physical activity and dietary calcium intake? A survey in 10,373 young French subjects. Med Sci Sports Exerc 1998 May;30(5):732-9. 2. Voss LA, et al. Exercise-induced loss of bone density in athletes. J Am Acad Orthop Surg 1998 Nov-Dec;6(6):349-57. 3. Bennell KL, et al. Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes. Br J Sports Med 1996 Sep;30(3):205-8. 4. Eichner ER. Sports anemia, iron supplements, and blood doping. Med Sci Sports Exerc 1992 Sep;24(9 Suppl):S315-8. 5. Weaver CM, et al. Exercise and iron status. J Nutr 1992 Mar;122(3 Suppl):782-7. 6. Altura BM, et al. Magnesium depletion impairs myocardial carbohydrate and lipid metabolism and cardiac bioenergetics and raises myocardial calcium content in-vivo: relationship to etiology of cardiac diseases. Biochem Mol Biol Int 1996 Dec;40(6):1183-90. 7. Lukaski HC, et al. Micronutrients (magnesium, zinc, and copper): are mineral supplements needed for athletes? Int J Sport Nutr, 1995;5 Suppl:S74-83. 8. Seelig M. Magnesium deficiency in the pathogenesis of disease. New York: Plenum Press; 1980. 9. Wenk C, et al. Methodological studies of the estimation of loss of sodium, potassium, calcium and magnesium through the skin during a 10 km run. Z Ernahrungswiss 1993 Dec;(4):301-7. 10. Tarnopolsky MA, et al. Mixed carbohydrate supplementation increases carbohydrate oxidation and endurance exercise performance and attenuates potassium accumulation. Int J Sport Nutr 1996 Dec;(4):323-36. 11. Venditti P. Effect of training on antioxidant capacity, tissue damage, and endurance of adult male rats. Int J Sports Med 1997 Oct;18(7):497-502. 12. Tessier F, et al. Muscle GSH-Px activity after prolonged exercise, training, and selenium supplementation. Biol Trace Elem Res, 1995 Jan-Mar;47(1-3):279-85. 13. Persson-Moschos M, et al. Plasma selenoprotein P levels of healthy males in different selenium status after oral supplementation with different forms of selenium. Eur J Clin Nutr 1998 May;52(5):363-7. 14. Hiller WD, et al. Medical and physiological considerations in triathlons. Am J Sports Med 1987 Mar;(2):164-7. 15. Cordova A. Behaviour of zinc in physical exercise: a special reference to immunity and fatigue. Neurosci Biobehav Rev 1995 Fall;19(3):439-45. 16. Cordova A, et al. Effect of training on zinc metabolism: changes in serum and sweat zinc concentrations in sportsmen. Ann Nutr Metab 1998;42(5):274-82. 17. Barrie SA, et al. Comparative absorption of zinc picolinate, zinc citrate and zinc gluconate in humans. Agents Actions 1987;21(1-2):223-8. 18. Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 19. Rokitzki L, et al. Alpha-tocopherol supplementation in racing cyclists during extreme endurance training. Int J Sport Nutr 1994 Sep;4(3):253-64. 20. Simon-Schnass I, et al. Influence of vitamin E on physical performance. Int J Vitam Nutr Res 1988;58(1):49-54. 21. Lemon PW, et al. Do athletes need more dietary protein and amino acids? Int J Sport Nutr 1995 Jun;5 Suppl:S39-61. 22. Shephard, RJ, et al. Immunological hazards from nutritional imbalance in athletes. Exerc Immunol Rev 1998;4:22-48. 23. Rohde T, et al. The immune system and serum glutamine during a triathlon. Eur J Appl Physiol 1996;74(5):428-34. 24. Newsholme EA, et al. The proposed role of glutamine in some cells of the immune system and speculative consequences for the whole animal. Nutrition 1997 Jul-Aug; 13(7-8):728-30. 25.Rohde T, et al. Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Med Sci Sports Exerc 1998 Jun;30(6):856-62. 26.Castell LM, et al. Does glutamine have a role in reducing infections in athletes? Eur J Appl Physiol 1996;73(5):488-90.
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Runners who don’t train well can have marathon of miseries
Today, as an estimated 20,000 runners begin their mad dash from Hopkinton to Boston, Dr. Malissa Wood, a cardiologist, four-time marathoner, and codirector of the Massachusetts General Hospital Women's Cardiovascular Health Center, will be setting up shop in the corner of the medical tent at the finish line.
As soon as they're finished, about 25 amateur runners will stroll or hobble over to Wood's corner to let her take a sample of their blood. They will also get a noninvasive test to see how well their hearts are working after the stress of running for about four hours. And, as they have done every year since 2003, Wood and her Mass. General colleagues will compare these postrace test results to the prerace exams done two weeks earlier.
The Mass. General findings on Boston marathoners — three published papers to date and two pending — are sobering and lend support to the idea that while moderate exercise is perhaps the most important thing a person can do for health, taking it to extremes, like a marathon, may be dangerous.
Among marathon runners, the biggest cardiac risk seems to arise in people who train the least. People who worked up to a marathon by running at least 45 miles a week for at least three to four months ''were golden. They didn't get into any trouble at all," said Wood. ''If they trained less than 35 miles a week, they were in big trouble."
Translated for the rest of us, this means that for people who are not in peak shape ''sudden, strenuous activity can trigger a heart attack," said Dr. Arthur Siegel, a 20-time marathoner and director of internal medicine at Harvard's McLean Hospital in Belmont.
Roughly 450,000 Americans run in marathons every year. And 325,000 do triathlons, which involves swimming, biking, and running, according to USA Triathlon, the sport's organizing body. Many of these are not well-trained athletes but newcomers who race to raise money for charities. That means, said Siegel, that in many such events, participants ''are getting older and slower. That's where the cardiac risk comes in, especially for middle-aged men with previously silent heart disease."
Moderation is the key, said Dr. Harvey Simon, an avid runner, former marathoner, Mass. General internist, and author of ''The No Sweat Exercise Plan," which advocates very moderate exercise — even as moderate as gardening and housework — instead of extreme exertion like marathoning.
''The greatest hazard of exercise is not doing it," said Simon.
''I used to preach 'No pain, no gain,' but now I say, ''No pain, big gain,' " he said. The whole ''aerobics doctrine" that a person needs a lot of strenuous exercise ''inspired the few but discouraged the many," he said. Even walking at the extremely leisurely pace of half an hour per mile has benefits.
Study after study has shown that moderate, regular exercise can indeed reduce the risk of heart disease, diabetes, stroke, hip fracture, and some kinds of cancer.
But exercising moderately takes patience and persistence. If you have not been exercising regularly, you should work up over several weeks to walking 45 minutes a day at least five days a week, said exercise physiologist Kerry Stewart at Johns Hopkins School of Medicine.
At first you may have to stop every few minutes and rest, he said. That's fine — just start up again. If you get chest pains or severe shortness of breath, of course, stop and call your doctor. If you have heart disease or have had a heart attack, check with your doctor before starting or substantially increasing your workouts.
You shouldn't underdo exercise, but you shouldn't overdo it, either. Chronic fatigue, trouble sleeping, muscle tiredness, nagging congestion or sore throat, persistent aches and pains, and depression are common signs that you may be working out too hard, said Siegel. To avoid this, try not to increase your exercise duration or intensity by more than 10 percent over any two-week period.
The easiest way to gauge whether you're working hard enough is to use the ''sing/talk test": Work hard enough that you can't sing but can talk.
Experienced athletes ''know how delicate the balance is between training to obtain optimal performance and overtraining to the point where muscle function begins to deteriorate," said Dr. Christopher Cooper, an exercise physiologist at UCLA. But for amateurs, finding that balance point can be hard.
As for marathoners, Wood and her Mass. General colleagues have found that running 26.2 miles can lead to clear signs of cardiac stress. They have found that cardiac troponin, a chemical that shows up in blood tests only when heart muscle is damaged, rises in 60 percent of runners, and in some, it rises so high that ''if you had just looked at these scores, these people would have been admitted to the hospital for heart attacks," Wood said.
They've found that another chemical, BNP, or brain natriuretic peptide, another red flag for cardiac dysfunction, goes up after a marathon in 60 percent of runners. Platelets also become activated and more likely to form the clots that can trigger heart attacks, according to a just-published paper by Siegel and Alexander Kratz, director of the hematology lab at Mass. General. And, as shown on echocardiograms, the heart's ability to relax after each beat remains impaired for at least several weeks in most marathoners.
Bottom line? You don't have to run a marathon to get into good shape. Just put on comfortable shoes, get out, and walk. Moderately. And consistently.
A balanced diet for runners
August 9, 2009
Filed under Diet And Nutrition, Running
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Top nutrition tips to get you started in running
Getting fit and active through a running training programme is a great way of keeping your body and mind fit and healthy. However, a balanced run training plan also requires a balanced diet, to ensure you have the right energy intake to suit your body's running workouts. Here's the realbuzz introduction to running nutrition, guiding you on the best things to eat if you're looking to build those all-important running energy reserves.
We are all becoming more aware of the physiological and psychological rewards of being physically active, notably through running. If you need to lose weight or want to avoid becoming overweight, then the best way is to increase your physical activity levels, and to reduce your dietary fat intake, which can be achieved by decreasing your intake of starchy and sugary carbohydrates.
Even if you didn’t lose weight, but became fitter, it would help you avoid the many health complications of being overweight and so increase your life quality and expectancy. Furthermore, taking part in regular running exercise or other sports also helps reduce your risk of developing heart disease, diabetes, osteoporosis and certain forms of cancer. And, not forgetting the important role that physical activity plays in your mental well-being.
So, the recommendation that everyone should accumulate 30 minutes or more of physical activity over the course of most days of the week is thoroughly justified. But how do we go about becoming more active? If you’re pretty sedentary at the moment, then what you need to do is to modify your lifestyle to build in more running or other physical activities.
So start by becoming less sedentary, for example decreasing the time you spend watching television, surfing the net or playing computer games. Next try to be more active, take the stairs instead of the lift, park further away from the supermarket, or get off the bus one stop earlier and walk the rest of the way. Then gradually add some sustained exercise to your daily routine, such as brisk walking, cycling or swimming.
Yes, the aim is to be doing at least 30 minutes of continuous exercise five days per week, but gradual is the key, so try three lots of ten minutes to start with, and take it from there. The next question is – how do we fuel these bursts of running and other physical energy?
Dietary considerations for runners
The dietary considerations for fuelling a healthy, active lifestyle can be found in more detail in the following sections, but here are the basics.
As we know, a healthy balanced diet is essential for good health. The key to making our diet healthy and balanced is simply everything in moderation, plus extra carbohydrates if you’re running or exercising.
But why the emphasis on carbohydrates? Well, no matter what type of exercise or running you do, your body will always use some glucose for energy. Glucose is formed from the breakdown of carbohydrates – the sugars and starches in your diet – and is stored as glycogen. However, the body can only store a limited amount of glycogen, so the stores need to be kept topped-up to avoid fatigue. If you don’t eat enough carbohydrates, but continue to exercise you will soon become sluggish and dizzy and your exercise goals will go right out the window!
The more physical activity you do, the more glucose your body uses, the more carbohydrates you need to consume to replenish your stores. Therefore, physically active people need to consume a diet where more than half of it comes from carbohydrate foods. The bulk of your carbohydrate intake should come from the starchy sources such as bread, rice, potatoes and pasta and the remaining from more sugary sources such as sugar, fruit and juices.
However, as most carbohydrate foods, for example pasta or sugars, are eventually broken down into glucose, one type is not necessarily better than the other. But, if you’re running regularly, you need to eat a lot of carbohydrates, and there is only so much bread and pasta you can eat, so this is where sugary snacks and drinks have a useful role to play, both in providing you with energy before you exercise, and in helping you restock your glucose stores after exercise, ready for your next bout of physical activity or your next big run.
Although you need to allow two to three hours after a large meal before exercising, a high carbohydrate snack within 30 minutes of training has several benefits. Eating 25-50g of rapidly absorbed carbohydrate just before exercise will not only improve performance, but will also help maintain your blood sugar levels and so prevent you feeling light-headed. There are plenty of portable high carbohydrate snacks to choose from – bagels, honey or jam sandwiches, cereal bars, bananas, watermelon, dried fruit, jelly beans, juice or a sports drink – so find something you fancy.
12 Reasons You’re So Tired and How to Bounce Back
When people ask you how you are, how do you respond? Do you say you're fine—or tired?
If you were too exhausted even to answer the question, you're not alone: Fatigue is endemic these days. Here are a dozen potential reasons behind that run-down feeling and how you can re-energize yourself.
1. You're bored.
Boredom happens when parts of your life have created a rut of routine, says clinical psychologist Judith Sills, Ph.D. "There's not enough zap in your brain," she says. Sills, author of The Comfort Trap (Viking, 2004), concedes that humans are creatures of habit, so routines are essential for life. But comforting routines and habits can become deadening. That's when lack of zing can translate into fatigue. There's a loss of energy when you have nothing to stimulate you, she says.
The fix: Do something new, Sills suggests. Even small changes, such as a two-day getaway, can be life-affirming. "There's a clear link between our emotions and the anticipation of satisfaction and physical energy," she says. Changing your routine also helps. Try driving down a different road or eating food you haven't tried before. "When you take in new information, your spirit feels a sense of possibility," says Sills. "It's mind food."
2. You have allergies.
Think of allergies as the body's way of fighting unwanted guests. The trouble starts when allergens, such as pollen, certain foods, or animal dander invade the mucous membranes of the eyes and throat, says Lily Pien, M.D., an allergist at The Cleveland Clinic. This triggers the body's antibodies to fight the invaders, causing a release of histamines. The body's reaction to the allergens is often excessive, leading to sneezing, shortness of breath or itching. "It's these reactions that wear you down, especially when they keep you from sleeping." she says.
The fix: "Don't misdiagnose yourself," says Pien, "Most people are allergic to more than one substance." She advises seeing an allergist and getting a skin test to determine the allergens that may be affecting you. Antihistamines and nasal steroid sprays are both typical treatments, she says, and adds that 20 percent of the U.S. population suffers from allergies.
3. You're over-caffeinated.
It seems like a contradiction, but caffeine, a stimulant to the central nervous system, can actually make you tired, says Cheryl Forberg, a registered dietician and the author of Positively Ageless: a 28-Day Plan for a Younger, Slimmer, Sexier You (Rodale Books, 2008). A once-a-day dose in the morning in tea or coffee is fine, she says. But people can create a vicious cycle when they keep ingesting more caffeine to counteract the exhaustion they feel after the previous dose wears off. And, she adds, the cumulative effects of the day's caffeine—such as increased heart rate and a rise in blood pressure—can also keep you from getting a good night's sleep.
The fix: Consider antioxidant-rich green tea, says Forberg. A cup of green tea contains 50 mg of caffeine, compared to coffee's 137 mg and black tea's 65 mg. Not eating or drinking high-caffeine foods and drink—including dark chocolate and certain soft drinks—from late afternoon on is also a step towards restful sleep. Keeping caffeine to a minimum is the best way to go, she says.
4. You're multi-tasking.
Doing one thing at a time is a luxury for most people. But multi-tasking has its downside. "When you multi-task, you need to switch back and forth from one project to another and monitor all the projects simultaneously," says Neal Roese, Ph.D., a professor of psychology at The University of Illinois at Urbana-Champaign. Multi-tasking is a big drain on glucose, which fuels everything the brain does, he says. Not surprisingly, studies show that too much flitting from one task to another ultimately leads to errors and fatigue. Ingesting sugar may keep you going temporarily, but eventually you crash.
The fix: The trick, says Roese, is to keep your projects down to a minimum; he suggests no more than three at a time. Prioritizing your projects and taking the short frequent breaks that allow glucose levels to be restored are also useful strategies.
5. You're anemic.
People with anemia typically don't have enough red blood cells in their body. And, because these blood cells are the body's transportation system for oxygen, fewer of these cells mean less oxygen makes its way to the cells—including that of the brain. "People whose cells get less oxygen may be less able to concentrate and they may feel less energetic, says Alan Greene, M.D., clinical professor of pediatrics at Stanford University and the author of Raising Baby Green (Jossey-Bass, 2007). The most typical type is iron-deficiency anemia, but loss of blood cells through internal bleeding can also be a cause. He says anemia is especially harmful to children, who need the oxygen to fuel their developing bodies and brains.
The fix: Greene advises taking a blood test. On a complete blood count (CBC) test, a low hematocrit indicates anemia (hematocrit measures what proportion of blood volume is made up of red blood cells). Testing serum ferritin, a measure of the body's iron stores, can detect iron deficiency, which can cause symptoms even before full-blown anemia develops. Eating iron-rich foods like lean meat, poultry and beans can help increase the supply, especially when accompanied by foods high in vitamin C. Greene also suggests women and children take supplements that contain iron. Men should speak with their physicians first before taking iron supplements, as their bodies don't easily excrete any excess, and too much of the mineral can also be a cause of fatigue.
6. You have poor posture.
Standing up straight looks impressive and, it turns out, has health benefits. If you hunch your shoulders forward, don't equally distribute your weight on both feet, or create an inward curve in your lower back, you're setting yourself up for fatigue, says Kathleen Koch, an exercise physiologist at The Cleveland Clinic. That's because it's harder for blood to nourish muscles that are being held in inefficient positions typical of bad posture. "Reduced blood flow means your heart and lungs have to work harder, and this makes you tired," she says. Sitting improperly and even running with poor form has the same effect.
The fix: Koch suggests strength and core training to address poor posture. For example, she says to correct slouched shoulders—a sign that the chest muscles are disproportionately stronger—you need to strengthen the muscles in the upper back. Because poor posture is a good indicator of muscle imbalance, it's important to train all muscle groups equally, she says.
7. You have an underactive thyroid.
One of the top medical reasons for a slow metabolism and low energy is hypothyroidism, says Nunilo Rubio Jr., M.D., assistant professor of endocrinology at The University of Texas Medical School at Houston. Women are more predisposed to the condition, which is from the thyroid gland's secreting less of its hormones. This, in turn, causes fatigue, as well as weight gain, intolerance to cold, and dry hair and skin. Rubio calls it the "turtle effect." Unfortunately, in most cases, it's the body's own autoimmune response that's to blame. The antibodies involved gradually can damage and, in some cases, destroy the thyroid, a condition known as Hashimoto's thyroiditis. In severe cases, says Rubio, metabolism slows down so dramatically that the patient usually requires an intravenously administered dose of thyroid hormones.
The fix: Rubio suggests those suffering from fatigue ask their physician for a blood workup to determine the level of thyroid- hormone activity. If you're diagnosed as having hypothyroidism, a doctor will typically start thyroid-hormone replacement therapy. Once thyroid-hormone levels are restored, energy usually returns to previous levels. (Although iodine deficiency is often linked to hypothyroidism, most people in the U.S. get adequate amounts by using iodized salt and eating iodine-containing food.)
8. You have undiagnosed heart disease.
A heart that's unable to pump blood efficiently has to work harder to transport oxygen throughout the body. Fatigue is the result, says Nieca Goldberg, M.D., cardiologist and author of Dr. Nieca Goldberg's Complete Guide to Women's Health (Ballantine Books, 2008). Several conditions can cause the heart to overexert itself, including clogged arteries, high blood pressure and heart-valve problems. Typically, fatigue due to undiagnosed cardiovascular condition manifests after exertion.
The fix: If you've ruled out anemia, hypothyroidism and infection, and you still feel tired, it's important to get diagnosed for potential heart problems, says Goldberg. Tests typically include an echocardiogram to see how the blood is pumped through the heart, and a stress test to reveal arterial blockages. Not pinpointing heart disease as early as possible can mean more severe symptoms over time, such as shortness of breath and fluid build-up.
9. You're not exercising enough.
It seems counterintuitive that doing nothing can make you fatigued, but it's true. "If you move, you'll feel less tired," says Dr. Koch of The Cleveland Clinic. When you're sedentary, she says, your metabolic rate decreases and you burn fewer calories, so you feel exhausted. Exercise gets that metabolic rate up, which means more energy, and not only the physical kind. People who say they're tired are often depressed, says Koch. Exercise increases the production of dopamine, a hormone that's a mood enhancer.
The fix: Literally, start with small steps. Koch says that research confirms that even a 10- to 15- minute daily walk provides cardiovascular health benefits But, she advises, don't forget to include strength training in the mix, which helps build lean muscle mass. Overall, increasing your amount of weekly exercise means you'll be able to burn even more calories, she says. And that means even more energy at your disposal.
10. You're dehydrated.
At least half of our bodies and 92 percent of our blood consist of water. "Water serves as a medium for the body to perform its life-sustaining functions, such as regulating body temperature and eliminating waste," says Toby Amidor, a registered dietician in New York City. "If you don't ingest enough water to help these metabolic reactions occur, you'll become tired or lightheaded."
The fix: At the first sign of thirst or dizziness, all you need is a small amount of liquid, as little as half a cup or water or fruit juice, says Amidor. Although many people drink huge quantities of water daily as a matter of course, she says many experts now suggest that people simply heed the body's signals for hydration. The water in fruits and vegetables also count as part of your intake, says Amidor. The caveat, though, is that older people often lose their sense of thirst and need to be reminded to hydrate on a more regular basis. For the rest of us, making sure we have access to water as needed—in portable non-plastic containers—is a good option.
11. You're pre-diabetic.
Glucose supplies energy to the body and brain. It's not surprising that not enough glucose will make you extremely tired. But the same is true when you ingest too much, says Dr. Greene. Normally, the act of eating signals the body to produce insulin which, in turn, fuels the cells with energy. But, says Greene, when you're pre-diabetic, your body can become insulin-resistant—overeating or ingesting too many simple carbs is often a factor. The result is all that excess glucose doesn't get into the cells, but rather it gets stored as fat or spills into the urine, and you grow tired.
The fix: A fasting blood sugar test will determine if you're pre-diabetic, says Greene. If you fall into that category, consider it a wake-up call to change your eating and exercise habits. Greene recommends a Mediterranean-type diet, consisting of whole grains, lots of fruits and vegetables and moderate amounts of healthy fats.
12. You have sleep apnea.
Many people with sleep apnea don't even know they have it, says Michael Breus, Ph.D., a clinical psychologist in private practice whose specialty is sleep disorders. Sleep apnea, which is typically caused by anatomical problems, impels the sleeper to stop breathing, sometimes as many as 150 times an hour. When breathing shuts down, even for only a couple of seconds, there's less oxygen supplied to the brain. The body senses the danger and wakes you to breathe. "In severe cases, this constant waking is comparable to total sleep deprivation," says Breus, who's author of Beauty Sleep: Look Younger, Lose Weight and Feel Great through Better Sleep (Plume, 2007).
The fix: See a medical professional who's certified in sleep medicine or clinical sleep disorders, says Breus. You'll be referred to a sleep center for diagnosis. The most popular form of treatment is a continuous positive airway pressure machine (CPAP), which shoots air through the nasal passages and throat while you're asleep. Other solutions include using nose filters, dental appliances to help correct jaw displacement, or surgery to remove excess throat tissue which tends to accumulate in overweight people. Weight loss may eliminate the condition entirely in some cases, says Breus.
Source: Coeli Carr for MSN Health & Fitness
Top 10 Disease-Fighting Foods
August 8, 2009
Filed under Diet And Nutrition
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 “Let food be your medicine, and medicine be your food.” When Hippocrates, the father of modern medicine, wrote those words more than 2,400 years ago, he was hundreds of years ahead of his time. Today, thousands of studies around the world confirm Hippocrates’ advice: What you eat has a powerful effect on your health. Functional Foods
The buzz today is about “functional foods” that provide health benefits beyond basic nutrition. Researchers say a diet high in fruits, vegetables, nuts and cold-water fish can make your immune system stronger and reduce your risk of heart disease, certain cancers, and age-related vision and mental problems. Supplements vs. Food
Studies say that taking supplements instead of eating whole foods doesn’t provide the same benefits and may actually increase your risk of disease. Researchers think that the combination of natural chemicals found in whole foods work together to promote health. 10 Important Disease-Fighting Foods
Enjoy the benefits of these top food choices, found on your grocery store’s shelves: Spinach
May prevent age-related vision problems; provides folate, a vitamin critical for reducing birth defects; reduces blood levels of homocysteine, an amino acid that increases heart disease risk; may protect the brain from aging Broccoli
High in sulforaphane, a naturally occurring compound that may help destroy tumor-causing chemicals; provides indole-3-carbinol, a phytochemical (nutrient that comes from plants) that may protect against estrogen-related cancers Salmon
One of the best sources for omega-3 fatty acid, a type of fat that may reduce the risk of blood clots and cardiovascular disease; has anti-inflammatory effect; may reduce risk of diseases such as diabetes, stroke, rheumatoid arthritis, asthma, inflammatory bowel disease, ulcerative colitis, some cancers and mental decline Nuts
Loaded with heart-healthy monounsaturated fats, omega-3 fatty acid and vitamin E; helps reduce total blood cholesterol Tomatoes
Rich in lycopene, a phytochemical that seems to play a role in preventing certain cancers Berries
High in cancer-fighting phytochemicals; appear to have brain-protective properties that may help prevent, and possibly reverse, age-related declines in memory and learning ability Beans / Legumes
Excellent source of protein, heart-healthy fiber, folate and antioxidants; may help reduce cholesterol levels Oats
Rich in a type of fiber that’s effective in reducing total and LDL (“bad”) cholesterol; effective in regulating blood sugar levels Purple Grape Juice, Red or Purple Grapes, Red Wine
High in a cancer-fighting compound that may also help reduce the risk of cardiovascular disease Coffee and Tea
Coffee: Appears to reduce risk of heart disease, type 2 diabetes and age-related cognitive decline |
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Top 5 Foods That Fight Diseases
August 8, 2009
Filed under Diet And Nutrition
This post will cover disease-fighting foods. Of course, immunity can be boosted by exercising regularly (not over doing it – that compromises the immune system), and hygiene as well. These 3 together are basic things that are in your direct control. We will look at what we can add to our diet to help defend ourselves better against diseases.
1. Soybeans
Soybeans are a known source of proteins, carbohydrates (soluble and insoluble fiber), potassium, magnesium, molybdenum etc. They are also a rich source of the very beneficial isoflavones compounds like genistein. It is also rich in Omega-3 fatty acids and iron. Studies have shown soybean’s significant role in preventing cardiovascular diseases, osteoporosis, promoting gastrointestinal health; lowering the chances of getting breast and prostate cancer and stabilizing blood sugars at healthy level as well as lowering BP and LDL.
2. Walnuts
Walnuts rank among the top dry fruits. They teem with health benefits such as cutting cholesterol levels, reducing risk of CVD, improving cognitive function etc. The Omega -3 in walnuts helps stabilize cardiac arrhythmia and prevents blood clotting within arteries. It prevents the hardening of arteries. Walnuts are rich in I-arginine – one of the essential amino acids that help blood vessels to relax. Not the least, walnuts boost your power to fight infections of the skin, asthma and arthritis.
3. Broccoli
Broccoli is packed with Vitamin C, Vitamin A, Calcium, Magnesium and Iron. In addition to that, broccoli is loaded with indoles and the very potent cancer fighting chemical sulforaphane and beta-carotene. This chemical produces enzymes that fight colon, bladder and ovarian cancers effectively. Broccoli also helps detoxify your system by removing free radicals that damage the heart. By the same virtue, it also protects the skin and helps maintain a healthy stomach flora. How’s that for a single vegetable!
4. Spinach
This leafy green is loaded with beta-carotene, B2, B6, A, C, K, iron and chlorophyll. It is also a good source of folate, magnesium, potassium, zinc, protein, dietary fiber, calcium, phosphorus, omega-3 fatty acids, niacin and selenium. Spinach protects against osteoporosis, heart disease, colon cancer, and arthritis, strengthens bones, purifies blood vessels, increases blood haemoglobin, cures bile related problems, and removes toxins from intestines.
5. Olives
This bitter Mediterranean food is a power fighter. Its sulforaphane boosts the body’s detoxification enzymes. Olives give cellular protection against free radicals. The Vitamin E present in olives work as anti-oxidants that neutralize free radicals. It also protects against heart diseases and supports gastrointestinal health. It is known to reduce cholesterol and chances of colon cancer. Apart from this, the polyphenols in olives may also help reduce the severity of asthma, osteoarthritis, and rheumatoid arthritis. Olives are famous for their anti-inflammatory property.
There are many more foods that I have not included such as oats, tomatoes, capsicums etc. Though the foods I have mentioned have multiple benefits, they could harm those who are allergic to them.
Eat right and stay fit!
20 Most Surprising Health Benefits of Coffee
August 8, 2009
Filed under Diet And Nutrition
By Sarah Irani
Although coffee gets a bad rap, it’s actually a medicinal food. In fact, this stimulating bean isn’t nearly so bad as we’ve all been taught. Although I’m skeptical about grande latte supplementation in the long run (it’s a drug, after all), I found myself surprised by much of the science on coffee. Poor Ponce de Leon; all this time he should have been searching for the espresso machine.
Step aside, acai. Here are 20 surprising health benefits of coffee.
Apparently, coffee and alcohol really do go together. Believe it or not, alcohol drinkers who also drink coffee regularly have a lower chance of developing cirrhosis of the liver. That’s not to say it’s a healthy lifestyle – obviously, lowering your alcohol consumption is better. But…science says…
Caffeine reduces risk of skin cancer. Sorry, venti quaffers, this prevention method is topical. Lotions containing caffeine (both from coffee and green tea) have been shown to prevent the occurrence of cancerous tumors on the skin – in murine trials, anyway.
Have a smile with your morning brew! If you’re a caffephile, you don’t need this Johns Hopkins study to tell you that a cup or two a day increases your sense of well-being and happiness. You can thank dopamine for that, which also contributes to coffee’s addictive nature. But be aware, the study also noted that more than 2 cups daily increases the risk of anxiety and panic attacks. Some people respond more readily than others – if you find yourself feeling jittery or nervous, ease up on the joe.
Caffeine may reduce chance of Parkinson’s Disease. A 30-year study has shown that non-coffee drinkers have a higher chance of developing Parkinson’s Disease than their coffee-drinking counterparts.
Most Americans get their antioxidants from coffee. That doesn’t mean it’s the best source of antioxidants, just that it’s the most consumed. But, it’s true, coffee is very high in antioxidants. As for me, I’ll stick to fruit.
Black gold. After petroleum, coffee is the second most valuable economic product in the world. Imagine the financial potential of running our cars on coffee grounds.
Coffee may cut colon cancer in women. A 12-year study on Japanese women found that drinking 3 or more cups of coffee per day may actually halve the risk of developing colon cancer. They found no beneficial effect from green tea on the colon – in this case, it was strictly a coffee thing.
Coffee and diabetes, that’s a tricky one. Even though a Finnish study shows that drinking large amounts of coffee can reduce the risk of developing Type-2 Diabetes, coffee drinkers who already have diabetes have a harder time controlling their blood sugar levels.
Coffee reduces muscle pain. After a hard workout, a cup or two of coffee has been shown to reduce muscle soreness (in women, anyway) more effectively than naproxen, aspirin and ibuprofen. (But don’t replace your water thermos with coffee.)
Coffee will detox your liver in surprising ways. This remedy is not one for drinking: we’re talking about the coffee enema. Some people swear by it – using a tube to introduce coffee into the rectum and colon in order to stimulate the liver to remove toxins. Definitely not for the squeamish.
Coffee may reduce chance of death from heart disease. Studies show that drinking 4-5 cups of coffee a day can make you less likely to die from heart disease. The researchers think it may have something to do with coffee’s anti-inflammatory effects.
The devil is in the grounds. When coffee, which originated in Ethiopia and became popular in the Arab world, was first introduced to Western culture, Christian priests denounced it as the devil’s drink, given to the Muslims as a substitute for the wine (Christ’s blood) they weren’t allowed to consume. The belief at the time was that any coffee-drinking Christian risked burning in hell forever. Hooray, progress!
Coffee may help with short term memory. It’s probably because of caffeine’s stimulant effects, but an Austrian study showed that volunteers given caffeinated coffee had better reaction times and short-term memory function than those who were given the cup of decaf.
For women, caffeine may prevent long term memory loss. Because caffeine is a psychostimulant, older women who drink 3 or more
cups of coffee or tea a day have less memory loss and cognitive decline than their counterparts who drink less or none. Unfortunately, caffeine consumption doesn’t seem to have any preventative effect against dementia.
Caffeine won’t cause hypertension. Some of the studies can be contradictory and confusing. What we do know is that for non-habitual coffee drinkers, those first few cups will cause a temporary rise in blood pressure, but for regular drinkers, a tolerance develops and won’t cause any long term, permanent increase.
The injustice of cheap coffee. No, it’s not just an injustice to your connoisseur taste buds; conventional coffee farming exploits workers and destroys communities in third world countries. On average, 5% of the profits actually make it back to the farmers, who are hungry, underpaid and treated badly. Why do they work on coffee plantations at all? Because in many cases, the plantations own the most fertile land (which was most often acquired unscrupulously) and the local people won’t survive from subsistence farming alone. How can you avoid supporting the cycle of poverty, corruption and injustice? Only buy Fair Trade certified coffee.
Pesticides in your brew. Because almost all coffee is grown in third world countries with less stringent laws than Europe or the United States, your non-organic cuppa is probably laden with chemicals. That’s not just bad for you, it’s bad for the farmers and the tropical ecosystems in which the coffee is grown. Go organic, will ya?
Pick your poison – literally. Caffeine is an alkaloid, which is a type of poisonous, bitter substance found in plants. Other alkaloids include strychnine, nicotine, morphine, mescaline, and emetine (the deadly ingredient in hemlock). Fortunately, in small quantities the bean is harmless, but it’s worth thinking about if you choose to use other drugs (both pharmaceutical and recreational).
The FDA has approved caffeine for babies. This doesn’t mean you can wake up your sleepy infant with a bottle of latte. Caffeine injections have been used medicinally since 1999 in the United States to stimulate breathing in infants who are experiencing apnea. It’s still recommended that pregnant and breastfeeding women keep their caffeine intake to a minimum, but a modest amount is safe.
Coffee can fight cavities. Just avoid all the sugar and milk! Actually, roasted coffee has some antibacterial properties, particularly against Streptococcus mutans, one of the major causes of cavities. By the way, these properties have nothing to do with caffeine, so decaf drinkers will get the same protection.
Despite the positive health studies, it’s best not to intentionally pick up the caffeine habit if you’re not already a regular coffee drinker. Even though some of the studies suggest drinking 3 or more daily cups to get the benefits, everyone is different. If it makes you jittery and sick to your stomach, stick to a milder pick-me-up like green tea or yerba mate. But if that morning cup makes you feel awake, alive and eager to greet the day, you might as well indulge (in moderation) in the world’s most well-loved drink.
What about Caffeine and Athletes
August 5, 2009
Filed under Diet And Nutrition
By Stephanie Nunes, RD
There is much confusion on the health effects of caffeine. I am going to address specific topics that may be of interest to athletes: Dehydration, Bone Health, Sports Performance, Cancer, and Heart Disease.
Extensive research has been conducted on the health effects and safety of caffeine consumption and the general consensus appears to be that moderate caffeine consumption (approximately 300mg/day) is safe. It is estimated that the average daily caffeine consumption among Americans is 280mg/day.
|
A Few Common Sources of Caffeine |
|
| Source | Caffeine |
| 8 oz Brewed Coffee | 135 mg |
| 1 oz Expresso | 30-50 mg |
| 8 oz Green Tea | 25-40 mg |
| 8 oz Black Tea | 40-70 mg |
| 12 oz Coca-Cola | 34.5 mg |
| 12 oz Diet Coke | 46.5 mg |
| 12 oz Mountain dew | 55.5 mg |
| SoBe No Fear | 158 mg |
| 1.45 oz Sweet chocolate bar | 27 mg |
| Exedrin | 65 mg |
Dehydration
Researchers used to believe that caffeinated beverages had a diuretic effect and caused dehydration. Recent research now shows that coffee, tea, and other caffeine-containing beverages do not affect hydration status on those who are already accustomed to consuming caffeine. Caffeine only has a diuretic effect if you consume large amounts of it (500-600 mg/day).
My advice: Enjoy your favorite caffeinated beverage while continuing to focus on maintaining proper hydration with fluids such as water, juices, sports drinks, etc.
Bone Health Research has shown that caffeine is not a significant risk factor for poor bone health when adequate calcium is consumed.
My Advice: Include at least 2 servings of calcium rich foods daily and add milk to your coffee or tea (my favorite is a non-fat mocha!)
Sports Performance
Early researchers thought caffeine's benefit on sports performance was linked to its ability to spare muscle glycogen and increase fatty acid metabolism. Now the current thinking is that the positive effects of caffeine have more to do with "mental energy". Studies on sports performance have shown that caffeine had a 24% improvement in endurance performance and 4% improvement in strength performance. The quantity used which showed the biggest improvement was 6 mg/kg body weight. Less than 3 mg/kg showed a smaller improvement or no improvement at all. It is also thought by some that the amount of caffeine needed for sports performance depends partly on "caffeine sensitivity".
Additional Note: Substances in coffee and tea can interfere with iron absorption.
My Advice: If you suffer from anemia, do not drink tea or coffee with your meals or within one hour after. The best advice would be to drink them an hour before eating. If you don't usually use caffeine but want to try it for sports performance, watch for stomach distress.
Cancer
The American Institute for Cancer Research (AICR) recently released an article, "The Truth about Caffeine and Cancer". The AICR stated that coffee is no longer associated with increased cancer risk. In fact, "because it contains antioxidants and anti-inflammatory compounds, coffee may actually boost health and possibly reduce cancer risk." Tea continues to show cancer combating benefits, especially green tea.
Heart Disease
Recent research has shown no relationship between caffeine ingestion and heart disease. However, there can be exceptions to this rule in that some may react differently to caffeine than others.
My Advice: Check with your physician if you are experiencing elevated blood pressure or arrhythmias.
Summary:
Caffeine beverages can be worked into an athletes meal plan as long as you pay attention to overall daily hydration, continue to eat/drink the recommended calcium products, and follow an overall balanced meal plan that meets your sports- specific nutrient needs.
Stephanie Nunes is a Registered Dietitian and runner residing in San Luis Obispo, California. Her private practice is "Rock Solid Nutrition" and she provides individual counseling, on-line counseling, lectures or presentations for specific groups, and nutrition related articles. If you would like to contact Stephanie for any of these services, her e-mail address is Rocksolidnutrition@sbcglobal.net.
Why Is Exercise Important?
August 2, 2009
Filed under Fitness
We all know we are supposed to exercise but we make excuses not to do it. However, why is exercise so important? Well exercising helps prevent diseases. It reduces the risk for heart disease, cancer, high blood pressure and diabetes. It can even improve your stamina and delay the aging process. That is good news for us women. We never want to age! Exercising makes, your heart and lungs work better so that daily activities become easier. Things like carrying those heavy groceries, playing with your kids and more. Not to mention regular exercise makes you feel better about yourself. I used to exercise everyday and I did indeed feel good and had more energy. There are three types of exercise Aerobic, Anaerobic, Stretching.
You do not have to do anything too strenuous at first. Take a walk; use the stairs instead of the escalator. Even these small steps can make a big difference. If you are trying to lose weight start small and make sure you eat a well balanced diet. Try cooking at home instead of those fat filled take out dinners. Exercise can also benefit your sleep patterns and make it easier to fall asleep and stay asleep. Also making sure you drink plenty of water can actually help you lose weight. I know from experience that this works. I drink a lot of water and a few years ago, it helped me to feel full and lose weight faster. Make sure to drink plenty of water when exercising to avoid dehydration.
Everyone should exercise including children, adults and the elderly. Children need to exercise to grow and develop strong bones. Far too many children are obese. As well, there are adults who are obese. This can lead to horrible health conditions. People need to realize that exercise is the fastest way to lose that weight. You should do some form of exercise a few times a week. Just do whatever you like, swimming, running, walking etc. It will make your body stronger, fitter and more flexible. Just remember to warm up with stretching exercises and then have a cooling down period the same way. Otherwise, you could end up with an injury. No one wants an injury when you are exercising.
Exercise also removes toxins and waste from the body. Without exercise they are stored as fat in the body. That is where water comes in to help flush these toxins from your body. In fact, for optimal health you should be expelling waste a few times a day. However, how many of us actually go to the washroom that often? No wonder we have problems! In this world of immediate satisfaction, we are told to reward ourselves with food. This is the wrong message for some people who are battling weight issues. We all need to get up from our seats, stretch, and move and buy something other then those sweet treats! Wouldn’t you rather be muscle toned, slim, and fit into those jeans then overweight and tired and flabby and have nothing to wear?
Training Benefits from running – how long does it take?
This is based on a minimum of doing three 30-minutes workouts each week.
After 1 Week
Fitness:
You will feel more energized with the 1% boost of endurance. Resting heart rate can drop by 1 beat per minute. This means your heart is getting stronger.
Weight:
If 25% overweight; people on a reasonable diet will start losing weight – others, nothing discernible yet.
After 1 Month
Fitness:
4% increase in aerobic capacity (less out of breath). Resting heart rate may drop by 4 beats per minute. A fit heart rate is between 50 and 70 bpm.
Weight:
Muscle tone is improved. If 25% overweight; another 4 – 6 lbs will come off - others, perhaps 1-2 lbs.
Blood Pressure:
If a person started with higher than normal blood pressure and/or weight, the systolic pressure should drop by 5-7 points and the diastolic pressure should drop by 1-2 points. This means that blood is flowing more easily to your muscles and organs.
Systolic is the top number measuring the maximum pressure produced in the large arteries by each heartbeat.
Diastolic is the bottom number measuring the constant pressure maintained in the arteries between heartbeats.
After 3 Months
Healthy changes start to become more obvious at this point!
Fitness:
10 – 15% total increase in aerobic capacity. Resting heart rate, on average, drops another 5 – 7 beats.
Weight:
Muscles will be a bit larger and more toned. If overweight, 12 – 17 lbs could go; others may start seeing a 5 – 10 lbs drop.
Blood Pressure:
Systolic pressure could be up to a 7 – 12 point drop and diastolic pressure could drop 3 – 8 points.
Cholesterol:
At this point there will be a change in cholesterol levels. There may be a slight reduction in total levels but a definite rise in 'good' HDL cholesterol. Every 1% rise in HDL lowers the risk of heart disease by 3%!
After 6 Months
Fitness:
15-20% total improvement in aerobic capacity. Resting heart rate may have dropped a total of 10 – 15 bpm. A bonus: Recovery after a workout is significantly shorter needing perhaps only 3 or 4 minutes. This means oxygen is used more efficiently within your body.
Weight:
The former overweight may have dropped up to 30 lbs. OR if the scale shows
no change
- Fat tissue is approximately 20% less dense than muscle, so it takes up 20% more space. Muscle burns 19 times more calories than fat. So a pound of muscle takes less space and burns more calories then a pound of fat. If that isn't enough – here is a picture I found. http://www.onemorebite-weightloss.com/muscle-to-fat.html
Blood Pressure:
8 -15 points total reduction in systolic pressure and 4-10 points in diastolic pressure.
Cholesterol:
At this point if the reading were 'abnormal' the change should be enough to make them 'normal' YEAH!
After 1 Year
Fitness:
18 – 25% better at burning oxygen than when you started!! To improve this even more-add in those long runs or run more than 3 times per week.
Weight:
It takes fewer calories to maintain your body weight so it will remain about the same. To lose weight, increase exercise or decrease calories. Note: I have never lost weight during marathon training – you have to eat to maintain that much intensity in training!
Blood Pressure:
A total drop of 8 – 18 points in systolic pressure and up to 10 points diastolic pressure.
Cholesterol:
Cholesterol levels have improved enough at this point to extend your life expectancy!
Just when you wondered if all that running was worth it . .
Summary
The bottom line – life - and more of it!
I RUN FOR LIFE!
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