In a recent episode of the Free Trail podcast, ultra runner Tom Evans revealed that he consumed “just under 800 mg of caffeine” during this year’s Black Canyon 100k. That’s equivalent to the Red Bull-sponsored runner guzzling 10 cans of said drink.
This amount of caffeine would be too much for most people, but it’s not unheard of for ultra runners to consume large amounts of caffeine during races. In fact, many ultra runners swear by caffeine, claiming that it helps them to improve their performance, focus, and endurance.
So, what’s the deal with caffeine and ultra running? Is it really beneficial? And, if so, how much should you take?
In this post, I’ll explain the science behind caffeine and ultra running, and I’ll provide some tips on how to use caffeine safely and effectively during your next race.
The benefits of caffeine for runners
Caffeine is the most widely consumed drug in the world, with an estimated 80% of adults consuming caffeine in some form on a daily basis.
For runners it helps reduce the perception of effort, making running seem easier and maintain pace for longer.
Where it particularly shines is in long distance running as it can delay hitting the dreaded ‘wall’. It does this by increasing your blood levels of fatty acids to be used as fuel. By doing so it preserves glycogen – the muscle’s preferred energy source – for longer, thus delaying the dreaded slowdown later in a race.
Caffeine also blocks the signals from the brain to the body which tell us to stop when we’re tired. This is particularly important during an ultra marathon to ensure runners remain alert and awake for many hours.
Pre-race caffeine consumption
Some runners will abstain from caffeine leading up to an event, in the hope of getting an extra boost on race day. I wouldn’t recommend this, however, as you’re more likely to leave yourself vulnerable to headaches and other symptoms of withdrawal.
If you’re normally a morning coffee drinker, then continue to consume a similar amount as part of your pre-race routine. If coffee isn’t available on the day, then an energy gel with added caffeine should do the trick. Plus you’ll also get some last minute carbs.

A typical cup of coffee has about 80 mg of caffeine in it. Depending on your rate of metabolism, the effects from it should last between 4-5 hours.
Caffeine strategy in 6-8 hour races
The most popular tactic is to hold off consuming caffeine until the second half of a race.
For races up to about eight hours, I recommend taking approximately 50 mg per hour about three hours in. This is to replenish the levels in your blood from the pre-race caffeine, which will begin decaying.
The source of the caffeine isn’t overly important, and most runners choose to consume gels with caffeine in them. Other options include drinks, chews and tablets.
Source | Caffeine (mg) |
---|---|
Normal coffee | 80 |
Red Bull (250 ml) | 80 |
Tailwind (per scoop) | 35 |
GU gel | 20 – 40 |
Science in Sport gel | 75 |
High5 gel | 30 |
Maurten Gel Caf 100 | 100 |
Caffeine Bullet (per chew) | 100 |
Can you take too much caffeine?
The recommended caffeine dosage for performance gains is between 3-6 mg per kg of body weight. This includes any caffeine taken before the event.
As an example, someone weighing 75 kg would be between 225-550 mg. Obviously if you know you’re sensitive to caffeine, it’s wise to stick to the lower end of the scale.
It’s important to acknowledge that you can overdo caffeine consumption, so monitor your usage. Taking on too much can impair your performance and lead to upset stomach, jitters and even adrenal fatigue.
Also, moderate doses of caffeine have been shown to have a similar performance effect as higher amounts. So while caffeine can give you a welcome boost when you need it, you don’t always need a lot of it.
Using caffeine to stay awake in a race
A lot of ultra marathons go into the night and the following day. For those who participate in events lasting longer than 20 hours, caffeine can be a vital ally to help you stay alert and awake.
Start your day as normal, with your usual pre-race breakfast and coffee. During the race, try and avoid all caffeine until after midnight. When you reach this point, start ingesting caffeine at doses between 80-100 mg per hour, for a maximum of four hours..
This should see you through to sunrise, which will help reset your circadian rhythms and give you a natural boost.
Experiment during training
These suggestions should only be used as a guide for you to start experimenting with your own caffeine intake. How you use it during a race should be influenced by your tolerance and previous experiences.
To that end, I recommend you use your long runs as an opportunity to try various forms of caffeine and monitor the effects it has on your body.
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