What is caffeine?

Caffeine is one of the most extensively studied ingredients in sports nutrition. It occurs naturally in coffee, tea and cocoa and is also included in pre-workout formulas, capsules, energy gels and sports drinks.

Its main effects are associated with the central nervous system. Caffeine temporarily blocks adenosine receptors, potentially reducing perceived tiredness and increasing alertness and concentration.

How can caffeine affect performance?

The International Society of Sports Nutrition reports that caffeine may provide small-to-moderate improvements across several forms of exercise. The most consistent evidence concerns aerobic endurance, although potential benefits have also been reported for muscular endurance, movement velocity, sprinting, jumping and some strength or power activities.

Responses vary considerably between individuals. Body mass, habitual caffeine intake, genetics, sleep, training time and personal sensitivity can all influence the outcome.

How much caffeine is commonly used?

Many sports studies use approximately 3–6 mg of caffeine per kilogram of body mass. Lower amounts, potentially around 2 mg/kg, may be sufficient for some individuals. Very high doses do not appear necessary for an ergogenic effect and are more likely to cause side effects.

Starting with the lowest effective amount is generally more appropriate, particularly for people who rarely consume coffee or other caffeinated products.

When should it be taken?

The most common timing is approximately 60 minutes before exercise. However, timing depends on the delivery method. Capsules and drinks may differ from caffeinated gum, gels or other rapidly absorbed formats.

Evening use requires additional consideration because caffeine may negatively affect sleep. A temporary increase in training intensity may not compensate for poor recovery caused by disrupted sleep.

Side effects and precautions

Possible side effects include nervousness, rapid heartbeat, digestive discomfort, headache, tremor and insomnia. People with cardiovascular conditions, high stimulant sensitivity, pregnancy or ongoing medication should seek professional guidance before using concentrated caffeine products.

Conclusion

Caffeine is one of the most evidence-supported ergogenic ingredients. It may improve alertness and selected aspects of exercise performance, but it cannot replace sufficient sleep, balanced nutrition and appropriate training.

References

Guest NS, VanDusseldorp TA, Nelson MT et al. International Society of Sports Nutrition Position Stand: Caffeine and Exercise Performance. Journal of the International Society of Sports Nutrition. Published: January 2, 2021.