Caffeine is widely present in many popular foods and beverages, known for providing a quick energy boost. What’s less well-known is its ability to directly enhance athletic performance.
Caffeine comes from various nuts, seeds, and leaves and works by blocking adenosine, a chemical in your body that makes you feel tired. By doing this, caffeine helps you feel more alert and awake. It also boosts the production of adrenaline, which is the hormone responsible for your body’s “fight or flight” response, giving you a burst of energy and making you feel ready to take on challenges.
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 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 dosage if you have not previously had anywhere near that amount. If this amount is 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 the risk of negative side effects such as increased heart rate, tremors, GI symptoms and headaches.
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 extremely 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.
Variability of 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.
How Does Caffeine Help?
One hypothesis that has been discussed is that the performance benefits from caffeine might be because of increased fatty acid utilisation 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 also enhances shorter performances that aren’t limited by glycogen stores, suggesting a different underlying mechanism.
More likely, the majority of the 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 occurs during exercise. Obviously this can allow people to push harder.
Beyond 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 vertical 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
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 associated 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.
Summary
While caffeine is commonly utilised, it still is relatively underrated.
It appears that most people seem to use caffeine for its energy boost, which brings increased wakefulness and alertness.
The reason it is underrated though is because people are often not particularly strategic with their timing or dosages. Also, it is not necessarily common knowledge that it can directly improve performance beyond simply reducing perceived effort.
