"When you look at the reasons for DNFing in ultra-marathons, the majority come from bad stomachs." - Tom Evans
Caffeine is a powerful performance aid - but it also carries real risks.
For ultra runner Tom Evans, caffeine isn’t simply about boosting energy. It’s about managing exposure across races that can last 20 hours or more. Used too early or too aggressively, it can create the very problems athletes are trying to avoid.
From the unpredictability of coffee strength to the stomach issues that end many ultra-marathons, Evans explained on his Ultra Sound podcast why caffeine strategy needs to be planned as carefully as any other part of race nutrition...
Tom, you've mentioned three different sources of caffeine - coffee, Red Bull and a gel. Which of those are you using for a race?
Well, typically I won't use coffee for a race. It's always really difficult to know exactly how much caffeine you've got in a coffee - each bean is different depending on how long ago it was roasted. It's different and it might keep changing as the profile of a coffee bean continues to develop.
Whereas with a Red Bull I know that in a normal can there are 80 milligrams of caffeine, which I know is what I need to take every hour.
So I know if got access to an aid station every hour, like at Western States for example, I can make that work quite comfortably. At UTMB it's a little bit different, the aid stations are more spread out, but I will only start using caffeine at UTMB when I start getting tired, because the race runs through the night and I don't necessarily want to take caffeine just before the race at 6pm because then I've got to be caffeinated for the next 20 hours.
It's really difficult to get it exactly right, but if I start feeling tired then it's something that I need to implement. If I'm not feeling tired then maybe I'll change my plans a little bit on the go, but during races Red Bull is usually the best option for me.
Why wouldn't you want to be caffeinated for those 20 hours at UTMB for example?
It's just such a long period, and I appreciate that there are risks associated with caffeine use.
You risk getting stomach issues and I guess that's the elephant in the room - the more caffeine you consume, the more chance you have of getting a bad stomach.
When you look at the reasons for DNFing in ultra-marathons - that means runners who did not finish - the majority of DNFs come from bad stomachs. I think that's linked to the fact that a lot of people don't necessarily train how they're going to race, and they then do something new on race day.
So what I'm trying to do is reduce the risk of that happening by basically having a picnic when I'm out on a long training run.
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