Answer to Question 1
Athletes gravitate to promises that they can enhance their performance by taking pills, powders, or potions. Unfortunately, they often hear such promises from their coaches and peers, who advise them to use dietary supplements, take drugs, or follow procedures that claim to deliver results with little effort. When such performance-enhancing aids are harmless, they are only a waste of money; when they impair performance or harm health, they waste athletic potential and cost lives. This highlight looks at scientific evidence for and against dietary supplements and hormonal preparations available to athletes
Answer to Question 2
Some research supports the use of caffeine to enhance endurance and, to some extent, to enhance short-term, high-intensity exercise performance. Caffeine may stimulate fatty acid release during endurance activity, but in contrast to what was previously thought, caffeine does not slow muscle glycogen use. Light activity before a workout also stimulates fat release, and unlike caffeine, also warms the muscles and connective tissues, making them flexible and resistant to injury.
Caffeine is a stimulant that elicits a number of physiological and psychological effects in the body. Caffeine may enhance alertness and reduce the perception of fatigue. The possible benefits of caffeine use must be weighed against its adverse effectsstomach upset, nervousness, irritability, headaches, and diarrhea. Caffeine-containing beverages should be used in moderation, if at all, and in addition to other fluids, not as a substitute for them.
Caffeine is a restricted substance by the National Collegiate Athletic Association, which allows urine concentrations of 15 milligrams per liter or less (equivalent to about 5 cups of coffee consumed within a few hours before testing). Urine tests that detect more caffeine than this disqualify athletes from competition.
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