Blog Post

Caffeine and Athletic Performance: Everything You Need to Know

Coffee Beans

Caffeine can be found in a huge range of commonly consumed beverages and foods, and it’s no secret that it delivers an energy hit. Not as common knowledge, however, is the way it can literally improve athletic performance.

Caffeine is derived from a range of nuts, seeds and leaves and acts as an adenosine receptor antagonist throughout the body. It increases the production of adrenaline, pushing your body into that “fight or flight” mode.

Over the years, caffeine has been shown to enhance athletic performance, with the bulk of these benefits thought to be due to its effect on the central nervous system, particularly, the reduced perception of effort and enhanced motor unit recruitment.

Caffeine’s efficacy as an ergogenic aid is widely recognised and has been observed in a range of modalities, including BOTH endurance and power based activities.

It is commonly assumed that caffeine is only beneficial for endurance athletes and does not provide any benefits for strength and power. While it is slightly less relevant for strength and power athletes, there is evidence that high dosages of caffeine can help improve one-rep max performance and power in general.

Dose IS Important

Studies have provided varying results when it comes to defining what is an effective dose to improve performance and there is definitely variation amongst individuals.

The current consensus is that as a broad range, 3-6mg/kg of body-weight is the gold standard for performance. 

This should be timed 30-60 minutes before the event. If using something that is more quickly absorbed, like caffeinated gum, then this range should be reduced to 15-30 minutes.

Endurance athletes can often find benefits at throughout that range, and sometimes even slightly lower. There can also be benefits for endurance athletes utilising small dosages such as 1-3mg/kg later on in races as well, rather than just before the start.

Strength and power athletes often benefit more from quite high dosages such as 5-6mg/kg of body weight.

For a lot of people, this is a large amount and it would be recommended to be cautious with this high a dosage if you have not previously had anywhere near that amount. And if this amount causing any detriments to your performance (e.g. GI distress) than the cons likely outweigh the pros, regardless of the outcomes in the research.

Higher doses than this typically do not provide any further improvement. In some cases, they may even result in poorer performance than lower doses.

Essentially, you should aim to find the dosage that is most effective for you personally, while minimising their risk of negative side effects such as increased heart rate, tremors, GI symptoms and headaches.

Caffeine Content of common australian products


Can You Just Drink Coffee? 

A food-first approach is often appealing. In a lot of cases I encourage a food-first approach where possible.

For caffeine it is a tricky one though.

One aspect of complexity is the volume that could be required to reach the required amount.

A coffee is generally 80-100mg of caffeine.

Based on this, if you were 80kg and aiming for 5mg/kg, that would require 400mg caffeine. This would be the equivalent of roughly 4 coffees.

So if you drank regular coffees, that would be a lot of liquid to consume. Alternatively, if you only had one coffee, you would be be having a sub-optimal amount of caffeine.

But to add more complexity, the caffeine content of coffee is extremeley variable.

One study from the Gold Coast identified that an espresso from different coffee shops could range from 25-214mg of caffeine. That is insane. 

Variablity of a caffeine content is not exactly an issue you want to have if you are trying to optimise your caffeine content.

You CAN use coffee, it just would lack a level of preciseness. 

Ben Desbrow Espresso Caffeine Variability

How Does Caffeine Help?

One hypothesis that has been discussed is that the performance benefits from caffeine might be because of increased fatty acid utlisation during exercise

If caffeine could increase fat utilisation during exercise, it would allow glycogen to be used at a lower rate and spared for later in events. This was hypothesised to be the mechanism by which endurance activities were improved.

By the mid-1990s though, it became clear that this mechanism was not the explanation for improved performance. The fat-mobilising and glycogen-sparing effects are not consistent in the research. Even in people who do respond to caffeine by releasing more fat into the blood, the effect appears to be non-existent after 10-15 minutes.

Performance increases are also seen in both responders and non-responders to caffeine-stimulated fat release. Caffeine is also beneficial for shorter performances that are not limited by glycogen, which would not be explainable by this mechanism either.

More likely, the majorty of the benefits benefits from caffeine occur due to antagonistic interactions with adenosine receptors in the central and peripheral nervous systems. 

At a minimum this can reduce the perceived level of effort that is occuring during exercise. Obviously this can allow people to push harder. 

Beyond that the reductions in perceived effort, caffeine can also directly increase central drive in the central nervous system which can explain some of the direct performance improvements.

One example of this is that it can improve muscle contractions via the release of calcium within the cell which explains improvements in things like lifting, sprinting and verticla jump performance.

Caffeine Tolerance

The topic of caffeine tolerance is pretty complex though. At this stage, the research seems mixed. But the current consensus seems to be that:

  • High habitual intake of caffeine does seem to reduce the benefit of caffeine when consumed for performance purposes.
  • Consuming a slightly higher amount of caffeine than usual intake can potentially offset this issue.
  • If habitual intake is very high, it probably does not make sense to go higher than that level.
  • The concept of withdrawing caffeine leading up to competition and then reintroducing it has theoretical merit, but the research that is available at this stage has not shown it to consistently provide any noticeable benefit.
  • Ideally, regular caffeine intake should be <3g/kg/day, which seems to mitigate all of these issues come competition day.

Downsides of Caffeine

Coffee being poured

While there are a lot of benefits to caffeine, there are also some downsides too.

The most commonly cited downside is the impact on sleep.

Once ingested, caffeine is slowly metabolised or degraded in the liver with a half-life of 3.5-5 hours.  That means that half the original caffeine remains in the blood after 3.5-5 hours. And then in the next 3.5-5 hours, only 25% of the original amount is left, and so forth. So there can still be trace amounts 24 hours after ingestion.

There is a lot of individual variation with this though. But this knowledge is useful to have since a lot of people think caffeine will be out of their system completely by the time they go to sleep.

A good rule of thumb is to avoid large amounts caffeine after 12pm. But this can be tricky to balance. For example, what if you have an event late in the evening? Sometimes it makes sense to make the tradeoff, for better performance. But for training on a consistent basis, the benefits of quality sleep outweigh the benefits of caffeine.

The other two main downsides are gastrointestinal distress and anxiety/jitters associated with caffeine.

Gastrointestinal distress is pretty individual. But if caffeine provides a 1-3% performance boost, that can be outweighed by performance loss assocaited with GI symptoms.

Anxiety and jitters also could outweigh the performance boost.

In some cases it could make sense either not to utilise caffeine, or use the lowest effective dose.


While caffeine is commonly utilised, it still is relatively underrated.

It seems like most people use it for the purposes of that energy hit that comes alongside it. This includes the wakefulness and alertness that comes alongside this.

The reason it is underrated though is because people are often not particularly strategic with their timing or dosages. And it also is not necessarily common knowledge that it can directly improve performance beyond simply reducing perceived effort.

By Aidan Muir

Aidan is a Brisbane based dietitian who prides himself on staying up-to-date with evidence-based approaches to dietetic intervention. He has long been interested in all things nutrition, particularly the effects of different dietary approaches on body composition and sports performance. Due to this passion, he has built up an extensive knowledge base and experience in multiple areas of nutrition and is able to help clients with a variety of conditions. One of Aidan’s main strengths is his ability to adapt plans based on the client's desires. By having such a thorough understanding of optimal nutrition for different situations he is able to develop detailed meal plans and guidance for clients that can contribute to improving the clients overall quality of life and performance. He offers services both in-person and online.