Caffeine has well-known benefits for athletic performance and might just be our favourite supplement of all, especially in coffee form.
It is the most widely consumed stimulant in the world. Caffeine is linked to increased heart rate, improved neural signalling and enhanced muscle contraction and relaxation. Research consistently shows it can improve performance across a wide range of endurance sports and short-duration, high-intensity efforts.
How Does Caffeine Work?
Caffeine is a central nervous system stimulant. In simple terms, it helps you feel more alert and energised.
Caffeine works by blocking adenosine receptors in the brain. Adenosine is a neurotransmitter that promotes relaxation and fatigue. When adenosine binds to its receptors, nerve cell activity slows.
Caffeine has a similar structure to adenosine, allowing it to bind to these receptors instead. Unlike adenosine, caffeine does not slow neural activity. Instead, it increases neuron firing, leading to heightened alertness and stimulation.
This process also increases the release of endorphins, often referred to as “feel-good” hormones. The result is improved neuromuscular function, increased focus and reduced perception of effort. Caffeine also causes blood vessels in the brain to constrict, which is why it can help relieve certain headaches.
Performance Impact of Caffeine
Caffeine has been shown to improve:
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Endurance capacity
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Time to fatigue
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Perception of effort
These effects have been observed across endurance sports such as cycling, running and rowing, as well as during short-duration maximal efforts.
In simple terms, exercise can feel easier and more manageable at the same intensity.
How Much Caffeine Should Athletes Take?
Current evidence suggests an effective dose is 3 to 6 mg per kilogram of body weight, consumed around 60 minutes before exercise.
For a 70 kg athlete, this equates to:
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Around 210 mg at the lower end
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Up to 420 mg at the upper end
Lower doses closer to 3 mg per kilogram may also be effective and are often better tolerated. These can be consumed before and during exercise and are ideally paired with a source of carbohydrate.
When precise dosing is required, caffeine tablets or powders are the most reliable option. For a food-based approach, a pre-training coffee alongside a banana is a simple and practical choice.
Are There Side Effects of Caffeine?
Caffeine is not recommended for adolescent athletes.
In adults, potential side effects may include:
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Nausea
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Anxiety
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Restlessness
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Insomnia
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Gastrointestinal discomfort
Individual tolerance varies widely. Because of this, both dose and timing should always be trialled during training, not for the first time in competition.
Is Caffeine Right for Everyone?
Caffeine can be a useful performance aid, but it is not essential.
Athletes who are sensitive to stimulants or who already experience high levels of anxiety or sleep disruption may not benefit from caffeine use. Like all supplements, caffeine should be considered within the context of overall nutrition, training load and recovery.
Exploring Other Evidence-Based Supplements
Caffeine is just one supplement with strong evidence for performance benefits.
If you want to learn more about another well-researched supplement, you can check out our article on creatine to understand how it works, who may benefit and how to use it effectively.
Key Takeaways on Caffeine
Caffeine is one of the most effective and well-researched performance supplements available.
When used strategically, it can improve alertness, reduce perceived effort and enhance endurance and high-intensity performance. As always, the biggest gains come from a solid nutrition foundation, with supplements providing small benefits on top.
Check out the other articles in our Supplement Series on protein powders, nitrates and creatine.