研究课题：咖啡因与运动（代谢、耐力与效能）
供稿：人体生物与营养学，圭尔夫大学，蒙特利尔，加拿大
主要内容：咖啡因是多数运动员饮食中常见的物质，现在常见于许多新产品中，如补充能量饮料，运动胶糖，酒精饮料和辅助食品。在大大低于IOC许可标准的低剂量下，咖啡因就可以起到强有力的产能辅助作用，因此对于训练和竞赛是有利的。咖啡因不直接促进最大氧容量，但可以使运动员在训练过程中的能量输出更大，或训练时间更长，也有证据表明在模拟赛跑条件下，可以提高速度及能量输出。这些效果在短至60秒长达2小时的运动过程中都可见到。关于咖啡因对力量的影响报道很少。但近来的工作提示对最大能力没有影响，但没有数据显示运动前摄入咖啡因会导致脱水、离子不平衡或者其他副作用。咖啡因可以与其他药物起协同作用，如肾上腺素、抗炎症因子等。男性和女性运动员的咖啡因药代动力学类似，比如给予一定剂量的咖啡因，代谢时间、绝对血浆浓度及代谢产物完全一样。另外，运动或脱水，不会影响咖啡因的药代动力学。目前的有限资料显示，经常服用咖啡因的人和从未服用的人对咖啡因的反应类似，戒断后也不会有什么严重后果。咖啡因通过在运动肌肉内制造一个有利的细胞内离子环境，从而促进每个运动单元的力量起作用。
结论：咖啡因可以使运动员在训练过程中的能量输出更大，或训练时间更长；可以提高速度及能量输出；可以改善耐力和抗疲劳能力。运动前摄入咖啡因不会导致脱水、离子不平衡或者其他副作用。
Caffeine and exercise: metabolism, endurance and performance. Graham TE. Sports Med. 2001;31(11):785-807.
Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada.
Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also been shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.
主要内容：咖啡因是多数运动员饮食中常见的物质，现在常见于许多新产品中，如补充能量饮料，运动胶糖，酒精饮料和辅助食品。在大大低于IOC许可标准的低剂量下，咖啡因就可以起到强有力的产能辅助作用，因此对于训练和竞赛是有利的。咖啡因不直接促进最大氧容量，但可以使运动员在训练过程中的能量输出更大，或训练时间更长，也有证据表明在模拟赛跑条件下，可以提高速度及能量输出。这些效果在短至60秒长达2小时的运动过程中都可见到。关于咖啡因对力量的影响报道很少。但近来的工作提示对最大能力没有影响，但没有数据显示运动前摄入咖啡因会导致脱水、离子不平衡或者其他副作用。咖啡因可以与其他药物起协同作用，如肾上腺素、抗炎症因子等。男性和女性运动员的咖啡因药代动力学类似，比如给予一定剂量的咖啡因，代谢时间、绝对血浆浓度及代谢产物完全一样。另外，运动或脱水，不会影响咖啡因的药代动力学。目前的有限资料显示，经常服用咖啡因的人和从未服用的人对咖啡因的反应类似，戒断后也不会有什么严重后果。咖啡因通过在运动肌肉内制造一个有利的细胞内离子环境，从而促进每个运动单元的力量起作用。
结论：咖啡因可以使运动员在训练过程中的能量输出更大，或训练时间更长；可以提高速度及能量输出；可以改善耐力和抗疲劳能力。运动前摄入咖啡因不会导致脱水、离子不平衡或者其他副作用。
Caffeine and exercise: metabolism, endurance and performance. Graham TE. Sports Med. 2001;31(11):785-807.
Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada.
Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also been shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.
