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Caffeine: A Performance-Enhancing Substance

Updated: Jul 23, 2023

When it comes to supplements, not many beat caffeine for improving exercise performance. In this article, we give you the lowdown on caffeine and how to implement it into your nutrition plan.

Caffeine is one of the most commonly consumed psychoactive (mind-altering) substances in the world, and is found naturally in coffee, tea, and cocoa. If you read last week’s article, you know all about how coffee relates to health, but as I’m sure you are well aware, it also packs a punch when it comes to caffeine. Whether you consume caffeine through coffee or other sources like energy drinks, gums, or sports gels, it doesn’t matter for performance. Read on to learn about how caffeine can improve performance and how much you need to take to experience the benefits.

Image source: WHMUC

Mechanisms for Improving Performance

The main way that caffeine is thought to improve performance is through its effect on the central nervous system (CNS), also known as the brain and spinal cord (1). Caffeine is a CNS stimulant—it improves the brain’s capacity to do things, which has a knock-on effect of improving physical performance. Caffeine consumption has been shown to reduce the rate of perceived exertion (RPE)—in other words, how difficult we find exercise to be. It has also been shown to reduce muscle pain and may potentially increase how much force we can generate with our muscles (1). It doesn’t take a genius to see how influencing these factors can improve exercise performance.

This is because caffeine binds to adenosine receptors, and blocks the action of adenosine (a chemical found in human cells). This in turn increases concentrations of certain neurotransmitters—chemical substances that transmit messages (impulses) across nerves, e.g., from the brain to muscles—such as serotonin, dopamine, acetylcholine, norepinephrine, and glutamate (1). Ultimately, this improves mood, vigilance, focus, and alertness for the majority of individuals, and may impact feelings of pain, motivation, and effort, helping to explain how caffeine can reduce RPE and muscle pain during exercise, potentially helping the muscles to produce more force during exercise.

Performance Benefits of Caffeine

Understanding how caffeine works helps to explain the research showing improved performance after taking caffeine. But now you may ask, “how big is the performance-enhancing effect?”

Endurance Performance

Numerous studies have shown a ~2–4% performance improvement in endurance exercise performance when consuming doses of 3–6 mg/kg (of body weight) of caffeine (1). The response to caffeine can be quite individual, as highlighted by a 2018 meta-analysis (a study combining the results of multiple other studies) including 56 comparisons of time-trial performance (~80% of which were done with cyclists). In this analysis, researchers contrasted caffeine to a placebo and found a performance difference ranging from -3.0% to +15.9% for caffeine (2). Interestingly, the researchers also found that the performance-enhancing effect of caffeine increased as the duration of exercise increased.

Muscular Strength, Endurance, and Power

While a number of meta-analyses have reported improvements in muscular strength (~2–7%) and endurance (~6–7%), others have shown no such improvements (1). Similarly, the research on caffeine and power (sprint and repeated sprint performance) is mixed. The effect on ballistic activities such as jumping, however, seems to show improved performance with caffeine ingestion (1).

Lido Lotefa of Florö SK (Norway)

Football Performance

In a 2012 study, caffeine consumption (3 mg/kg) improved jump height, running speed, total distance covered, and the number of sprints throughout a match in semi-professional footballers compared to when they consumed a placebo (3). In another study, caffeine consumption (6 mg/kg) improved jump performance and passing accuracy compared to placebo consumption (4). In another, 15-metre sprint time and explosive leg power (measured by countermovement jump) were improved when footballers consumed a caffeine (3.7 mg/kg) and carbohydrate drink compared to just a carbohydrate drink (5). However, these findings are not always observed—in a study of young (~17 year-old) footballers, caffeine showed no significant performance benefits on matchday versus placebo (6). This may reflect the fact that there can be differing individual responses to caffeine.

Optimal Caffeine Intake

To get the most from caffeine, there are best practices from the literature. Despite the fact that there are data suggesting doses as low as 2 mg/kg of body weight can elicit performance improvements, an optimal dosing strategy is defined as ~3–6 mg/kg about 60 minutes prior to exercise (1). For most people, this is about 2–3 cups of coffee, but energy drinks and gums, etc. are just as effective at providing caffeine for performance. For a 70 kg individual, 3–6 mg/kg would equal 210–420 mg of caffeine, which as I mentioned, could be consumed through 2–3 cups of coffee or 1.5–2.5 cans of Monster.


  • Because the half-life of caffeine—which is the time taken for half of what you consumed to leave your system—is about 4–6 hours (but can be up to 10 hours!) (1), it is not recommended to consume it later in the day (after lunchtime). So if you’re training in the evening, you’re probably best not consuming it beforehand.

  • This is because caffeine can negatively impact both sleep quantity and quality, which can reduce the rate of recovery (1).

  • If you have an important match in the evening, it may be worth sacrificing your sleep that night for a potential performance improvement. That call will depend on your priorities.

  • For some people, excess caffeine can cause anxiety and jitters, so it may not be worth taking if it negatively impacts your mental state.

  • Caffeine can stimulate bowel movements, so ensure you test this strategy in training before matchday!

I hope you enjoyed learning a bit more about caffeine and take this information on board. Why not join us for a training session and see if a pre-training coffee can improve your passing accuracy? For enquiries, you can reach us at [email protected].

All the best!

Patrick Elliott, BSc, MPH

Health and Nutrition Science Communication Officer at Training121

Founder of Just Health — IG:

Health Disclaimer: This article is for informational and educational purposes only, and is not a substitute for professional advice. For health advice, speak to a physician or other qualified health-care professional, and for nutrition advice, speak to a qualified nutrition professional (e.g., registered dietitian). The use of information on this app/site is solely at your own risk.


(1) Guest NS, VanDusseldorp TA, Nelson MT, et al. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18(1):1. Available at:

(2) Shen JG, Brooks MB, Cincotta J, Manjourides JD. Establishing a relationship between the effect of caffeine and duration of endurance athletic time trial events: A systematic review and meta-analysis. J Sci Med Sport. 2019;22(2):232-8. Available at:

(3) Del Coso J, Muñoz-Fernández VE, Muñoz G, et al. Effects of a caffeine-containing energy drink on simulated soccer performance. PLoS One. 2012;7(2):e31380. Available at:

(4) Foskett A, Ali A, Gant N. Caffeine enhances cognitive function and skill performance during simulated soccer activity. Int J Sport Nutr Exerc Metab. 2009;19(4):410-23. Available at:

(5) Gant N, Ali A, Foskett A. The influence of caffeine and carbohydrate coingestion on simulated soccer performance. Int J Sport Nutr Exerc Metab. 2010;20(3):191-197. Available at:

(6) Pettersen SA, Krustrup P, Bendiksen M, et al. Caffeine supplementation does not affect match activities and fatigue resistance during match play in young football players. J Sports Sci. 2014;32(20):1958-65. Available at:

Technical Terms

Caffeine: A substance found in coffee that is a central nervous system stimulant, meaning that it improves attention and cognitive performance, and also improves a range of exercise performance outcomes.

Psychoactive: A substance is said to be psychoactive if it can alter the mind.

Central Nervous System: This refers to the brain and spinal cord.

Rate of Perceived Exertion (RPE): This refers to how difficult a task is, and is often measured on a scale from 6 (super easy) to 20 (couldn’t be any harder), called the Borg Scale.

Adenosine Receptors: These are receptors in human cells that allow for adenosine to bind, which reduces the concentrations of some neurotransmitters in the blood.

Adenosine: An organic chemical in the body that is a building block for ribonucleic acid (RNA).

Neurotransmitters: A chemical substance which is released at the end of a nerve fibre by the arrival of a nerve impulse and, by diffusing across the synapse or junction, affects the transfer of the impulse to another nerve fibre, a muscle fibre, or some other structure. Examples: serotonin, dopamine, norepinephrine, etc.

Meta-analysis: A type of study that combines the results of a number of other studies that look at the same thing, and produces a summative estimate of the effect or association of what’s being studied. For example, a meta-analysis of five studies looking at smoking and lung cancer would combine the results from all five studies into one overall result, with the intention of providing a better estimate of the true effect of smoking on lung cancer.

Placebo: A substance without medical effects that may benefit the individual consuming it because they believe it will cause them a health or performance benefit. Placebos are important in research, and if possible, researchers try to test the item/food/supplement they're researching against a placebo to see if there is a difference in effect between the two, which allows them to see if the tested item/food/supplement produces a "real" effect or not.

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