Does Caffeine Improve Performance

Plus! How much? When? And side effects.

Author

Mark Christie
January 20, 2025 • Estimated Reading Time: 9 minutes

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IN TODAY’S ISSUE
Does Caffeine Improve Performance?

Caffeine! We as humans, love it. Coffee comes second to water as the most drank beverage in the world, with over 2.25 Billion cups of coffee consumed across the world everyday!

Next to Creatine, it’s one of the most studied supplements in the world and can come in a variety of sources, from coffee beans to dedicated pre workout drinks.

What You'll Find Out

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WHAT’S UP
Does Caffeine Improve Performance?

In January 2021 the Journal of the International Society of Sports Nutrition published an article (Guest et al., 2021), stating that caffeine has consistently shown doses of 3-6 mg of caffeine per KG of bodyweight actually boosts exercise performance. NOTE: mg, not grams! Please do not read that as grams.

Doses over the 3-6 mg per KG of bodyweight (~9 mg per KG of bodyweight) showed signs of side effects and did not improve performance. It would be recommended to stick within the range which has been proven to show signs of performance enhancement, with little to no side effects.

The effect of caffeine on performance as stated by this review article (Martins et al., 2020), showed that caffeine had a positive effect on the CNS (Central Nervous System) through reducing the perceived exertion rate, boosting reaction time and alertness.

It is worth noting that although the general trend of literature cites benefits to caffeine consumption on performance, some studies have shown to have very little to no benefit for some individuals.

SCIENCE BRO
How Much Caffeine?

From the study by (Guest et al., 2021) cited above, we know that 3-6 mg of caffeine is generally recommended. However everyone has different caffeine tolerance levels due to how fast some people metabolise caffeine in the liver and habitual caffeine intake, which can build up a tolerance and dull the effects of caffeine supplementation on performance.

It can take only take 2-4 days of regularly consuming 50 - 100mg of caffeine per day to develop a tolerance. Most people, myself included, partake in daily cups of coffee, with an average cup of coffee containing roughly 95 mg of caffeine and a double espresso roughly 125mg of caffeine (this number can vary massively depending on what type of coffee). On top of that, most fizzy drinks have caffeine in them, so just take note of how much you normally consume on a daily basis.

PERSONAL RECOMMENDATION

We would also recommend starting at the lower end of this recommended scale or even slightly lower, after all we don’t want to consume more than we need to in order to get a benefit from it. We want to keep our tolerance low. The higher your tolerance, the higher dose you will need to consume to get a benefit when taking it for your training.

SCIENCE BRO
When?

Caffeine is usually consumed 30-60 minutes before a training session. Depending on how quickly your body metabolises caffeine and how much food you have in your stomach will determine how quickly you feel the effects of caffeine in your system.

Something you should take consideration of is caffeine’s effect on sleep.

A study by (Drake et al., 2013), came to the result that caffeine doses of 400 mg, when consumed upto 6 hours before bedtime significantly disrupted sleep, reducing sleep time by 1 hour. Of course this will vary on a person to person basis depending how you react to caffeine.

Caffeine has a half life of upto 7 hours for adults according to the findings by this review article (Temple et al., 2017).

If you train late at night it could be a smarter choice to forget about the caffeine or at least take a low enough dose that it doesn’t affect your sleep. Sleep disruption and the effect it will have on your performance, especially accumulated over several days, is not worth the performance benefits delivered by caffeine to improve one training session.

If you are used to taking pre workout before the gym, there are caffeine free options to consider.

TL:DR
Key Takeaways & Practical Applications

  • 3-6 mg per KG of body weight is optimal for performance enhancement, with doses over 6mg showing side effects.

  • Caffeine can have a positive effect on rate of perceived exertion, alertness and boost reaction time.

  • The benefits from caffeine can vary massively depending on daily habitual caffeine intake due to building up a tolerance.

  • We recommend starting at the lower end of the scale and only increase when necessary to see performance benefits.

  • Caffeine has a half life of upto 7 hours for adults, and doses can disrupt sleep when consumed upto 6 hours before bedtime.

That’s it for today ✌️

If you have any questions you’d like answered, topics you would like discussed, or perhaps some feedback, email them over to me at: [email protected]

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