Caffeine is naturally occurring chemical compound that functions in the body mainly as a mild nervous system stimulant. See how it affects your performance.

Caffeine is naturally occurring chemical compound that functions in the body mainly as a mild nervous system stimulant. It has been shown to enhance performance in sprints, in all-out efforts lasting 4-5 minutes, and in longer performance tests.


It appears caffeine enhances performance in shorter events through four interrelated neuromuscular effects:

  1. Lowering the threshold for muscle recruitment.
  2. 改变激发收缩耦合。
  3. Facilitating nerve impulse transmission.
  4. 增加肌肉内的离子运输。

In longer events, caffeine delays fatigue by reducing the athlete’s perception of effort. It increases the concentration of hormone-like substances in the brain called ß-endorphins during exercise. The endorphins affect mood state, reduce perception of pain, and create a sense of well-being.

Caffeine has also been found to delay fatigue during exercise by blocking adenosine receptors on fat cells. As a result, caffeine increases the level of free fatty acids in the bloodstream and thereby increases fat burning during exercise. This latter effect of caffeine used to be considered the major mechanism by which is enhanced endurance performance, but it is not known to be a minor factor. In fact, for those who normally maintain a high-carbohydrate diet it is virtually a non-factor.


Caffeine Is A Diuretic

Caffeine is a diuretic, meaning that it increases urine production, which could theoretically exacerbate dehydration during exercise. However, exercise negates this effect if caffeine. In a recent scientific review, researchers from the University of Connecticut wrote, “Dietitians, exercise physiologists, athletic trainers, and other sports medicine personnel commonly recommend that exercising adults and athletes refrain from caffeine use because it is a diuretic, and it may exacerbate dehydration and hyperthermia. This review, contrary to popular beliefs, proposes that caffeine consumption does not result in the following: (a) water-electrolyte imbalances or hyperthermia and (b) reduced exercise-heat tolerance.”


咖啡因通常在比赛前30到60分钟被耐力运动员使用,以提高竞争性能。咖啡因的细胞生成作用是剂量依赖性的。最大效果以每公斤体重5至6毫克的剂量观察到最大效果。对于150磅的跑步者来说,这大约为340-400毫克,或者您在14至17盎司滴水的咖啡中获得的咖啡因量。平均跑步者必须消耗的最小咖啡因量为可测量的麦克形效应约为每公斤体重2 mg。

It makes less sense to use caffeine as a daily workout performance enhancer, for two reasons. First, workouts are seldom maximal efforts. Second, the ergogenic effects of caffeine consumption decrease with habituation. For this reason, if you are a regular coffee drinker, you should cease coffee consumption four to six days before participating in a race.

In moderation, caffeine consumption does not cause any health problems. In fact, a daily cup of joe is good for you. The health benefits of coffee come from its caffeine content and its unique blend of antioxidants. According to Harvard Medical School, “Studies show that the risk for type 2 diabetes is lower among regular coffee drinkers than among those who don’t drink it. Also, coffee may reduce the risk of developing gallstones, discourage the development of colon cancer, improve cognitive function, reduce the risk of liver damage in people at high risk for liver disease, and reduce the risk of Parkinson’s disease.”

However, heavy caffeine use can cause or exacerbate problems ranging from headache to insomnia, and it is possible to become physically dependent on the drug. Caffeine is especially harmful when used as a means to stimulate artificial wakefulness or energy in those suffering from conditions such as chronic fatigue. So if you do like caffeine, limit yourself to one mug of coffee or green tea in the morning. Those who rely on regular “caffeine injections” throughout the day are well advised to cut back.

Caffeine and Sports Drinks

An alternative to taking a single large dose of caffeine prior to racing is to consume a caffeinated sports drink throughout races. In a recent study, conducted at the University of Birmingham in England, looked at the effect of caffeine on exogenous carbohydrate oxidation (i.e. the rate at which carbs consumed in a supplement are burned) during exercise. Cyclists received either a 6% glucose solution, a 6% glucose solution plus caffeine, or plain water during a two-hour indoor cycling test. Researchers used indirect calorimetry to measure the amounts and proportions of fat and carbohydrate oxidized during the test.




这项新研究表明,使用含咖啡因的运动饮料,例如加入咖啡因may be the best way to go in races.