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Should You Cut Out Caffeine Before A Race?
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Should You Cut Out Caffeine Before A Race?

Caffeine as a drug offers diminishing returns with each use and for many people is just a constant background noise in their system, no longer offering an energetic boost, more a helping hand to get them through the day. To utilise caffeine in sport and our daily life we need to understand how long it affects us for and how we can leverage this knowledge so that caffeine acts as a sail on our ship rather than just hoisting up the anchor. So do we need to cut out caffeine for a few hours, a few days or a few weeks before a race to benefit from its power?

The Impact of Caffeine Varies Dramatically

Despite caffeine being the oldest drug known to man it is only recently that we have begun to understand its impact in more than just general terms. Studies have averaged out their data to give us answers unreflective of anyone, (did you know that most humans have more legs than the average human for example[1], but as explained in a previous blog we now know that humans can be grouped in three distinct groups, based on our genetic disposition to metabolising caffeine, which explains the huge disparity in the numbers given below. Scientific tests need to be redone for each of the three groups to be truly useful, but until then if there is a variation in the findings, map yourself to the relevant end based on whether you’re a fast (50%), medium (40%) of slow (10%) metaboliser of caffeine.

How We Metabolise Caffeine Based On Our Dna
How We Metabolise Caffeine Based On Our DNA

How Long Does Caffeine Stay In Our System?

The general consensus is that the half-life[2] of caffeine is 3-7 hours in adults[3],

although numerous external factors impact this significantly including:

  • Smokers metabolise caffeine 50% faster than non-smokers[4]
  • Oral contraception doubles the time to metabolise caffeine[5]
  • Pregnancy more than doubles the half-life of caffeine[6]

Therefore a smoking pregnant lady using oral birth control for some reason would …. (Please do not do this). One person with alcoholic hepatic disease was even found to have a caffeine half-life of 168 hours[7] so if they wanted to get a good night’s sleep they would have needed to have a coffee at this time last week.

But in general if you were to drink three strong coffees (120mg caffeine) spaced out every 3-3.5 hours from 9am a fast metaboliser would only have 50mg of caffeine in their system by 9pm whereas a slow metaboliser would have around 300mg and still have over 100mg caffeine in their system when they woke up the next day.

It’s very easy to see how caffeine can build up in our systems over time, so depending on your intake and build up it may take anything between few hours and a few days to completely clear yourself of caffeine. This does not however mean that you have necessarily reset your system and can start afresh as if you’d never had caffeine before. The body builds up a tolerance to caffeine and undoing this tolerance takes longer.

Why Do We Build Up A Tolerance To Caffeine?

Caffeine reduces your tiredness by binding to brain receptors, stopping the chemical adenosine from blocking them and making us feel tired. (We go into greater detail in our blog Caffeine Naps: Why You Should Take Caffeine Before You Sleep)

Regular caffeine use causes the brain to grow additional adenosine receptors to compensate and as a consequence we therefore need to consume larger doses of caffeine to bond to the additional receptors to keep sleepiness at bay.

We’ve not been able to find any research into exactly how long it takes for your body to reset itself to its pre-caffeine levels, but most estimates seem to be between one and two weeks. Interestingly though some studies have shown that while resetting your body’s tolerance to caffeine will reduce your tiredness, it might not be necessary for athletic performance.

Caffeine Bullet Founder David Hellard Winning the Comrades Ultra Marathon Event

Should You Caffeine Fast Before A Race?

A study[8] published in the Journal of Applied Physiology tested the performance of cyclists during three 30 minute time trials for two groups - regular caffeine consumers and abstainers. Both groups had comparably faster times using caffeine vs a placebo. So it appears you don’t need to go cold turkey before a big race to benefit from caffeine.

How Long Before A Race Should You Cut Out Caffeine?

If your race requires you to stay focused for example adventure racing then reducing your caffeine intake will increase your overall alertness and the impact caffeine has on you when you take it. However for sporting performance alone going cold turkey does not appear to be necessary to benefit from caffeine. Depending on how much caffeine you consume and your metabolism your body can be caffeine free from within 6 hours to up to 4 days, so before any big event just cut the caffeine for a few days and then go smash that PB!

About Caffeine Bullet

Caffeine Bullets are performance enhancing energy chews with 100mg* caffeine and 4 types of electrolytes, formulated for athletic performance, to be taken before and during exercise to improve endurance, increase alertness and reduce the perception of pain. Far more convenient and concentrated than a gel, the caffeine is absorbed through your gums, to give you a more pronounced effect up to 3 times faster so that you can train harder and perform better.

Available in two flavours:

  • MINTense: Delivers a refreshing blast of spearmint that will awaken your senses. With each chew, you'll experience a burst of minty fresh flavour that revitalises your taste buds and fuels your energy levels. So good that it secured investment from notable Dragons, Steven Bartlett & Peter Jones, on the show "Dragons' Den."

  • ChocoLIT Orange: Has a unique combination of energising and delicious flavours. A perfect blend of dark chocolate, orange zest, and caffeine. This chew is designed to give your body an energy boost in an enjoyable way. Oh, and did we mention they're award-winning? They clinched the Editor’s choice for best value race nutrition at the Women's Running Awards in both 2020 and 2022!






[5] Benowitz NL (1990). "Clinical pharmacology of caffeine". Annual Review of Medicine. 41: 277–88. doi:10.1146/






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