Caffeine

Caffeine is a naturally occurring stimulant that blocks adenosine receptors in the brain, reducing the sensation of fatigue. In sport it is taken as coffee, tablets, gum or as an ingredient in pre-workout products.

What published research reports

The International Society of Sports Nutrition position stand on caffeine and exercise performance (2021) reports that caffeine consistently improves aerobic endurance performance, and to a smaller and more variable degree can improve muscular endurance, strength, sprinting, jumping and sport-specific performance. It states the effective dose range in the literature is about 3–6 mg per kg of body weight, taken most commonly around 60 minutes before exercise, and that doses of 9 mg/kg and above raise the incidence of side effects (anxiety, insomnia, gastrointestinal upset) without improving performance further. The document also reports large individual variation, partly genetic, in response to caffeine, and notes that caffeine taken late in the day can impair sleep.

References

• Guest NS, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18:1. JISSN