SQUADRUN – Real people, extraordinary portaloo moments
Caffeine is the most widely used performance drug in endurance sport, which is funny when you think about it. We love to dress running up as some noble communion with nature. Sunrise. Birds. Mountains. Personal growth. But peel back the lycra and what you often find is a half cooked ape in expensive shoes trying to run faster because she had a double espresso and now feels like destiny has chosen her.
And to be fair, caffeine works.
Not in a mystical way. Not because your “body just needed it.” Not because your pre race flat white from the pop up coffee cart had “good vibes.” It works because caffeine reliably improves endurance performance for a lot of athletes, mainly by blocking adenosine receptors, reducing perceived effort, increasing alertness, and helping you access a bit more output when things start to sting. The research on endurance performance is actually pretty solid here, and moderate doses are where the benefit tends to live.
That matters because long distance running is not usually lost for lack of poetry. It is lost because the pace feels too hard at 28k, because your brain starts bargaining with you at 52k, because the hill that looked “undulating” on the course profile turns out to be a bastard. Caffeine can help with that. It does not make you fitter. It does not replace training. It does not forgive stupidity. But it can make a hard effort feel slightly more manageable, and in endurance sport that is a very real weapon.
The important bit is that more is not better. This is where endurance athletes, being endurance athletes, often lose the plot. If a useful dose is good, then a monstrous dose must be amazing. So before the race they neck a coffee, a gel with caffeine, a pre workout, half a can of something neon, and then wonder why their heart rate is in low earth orbit and they are clenching their arse cheeks at the first downhill.
The current evidence points pretty consistently toward about 3 to 6 mg per kilogram of body mass as the range most likely to improve performance. Some athletes seem to benefit from lower doses, around 2 mg per kilogram, especially if they are more sensitive or are taking caffeine during the event rather than all at once before it. Very high doses, around 9 mg per kilogram or more, do not appear necessary for performance and are much more likely to cause side effects.
So what does that mean in real life?
- For a 60 kg runner, 3 to 6 mg per kg is 180 to 360 mg.
- For a 70 kg runner, it is 210 to 420 mg.
- For an 80 kg runner, it is 240 to 480 mg.
That is already a decent whack. It is more than one polite little coffee. And this is where people get caught out, because caffeine content in coffee is messy. One café coffee might be mild and civilized. Another might feel like licking a battery. Capsules, tablets, gels, and chewing gum are much easier to dose accurately than coffee. Research supports anhydrous caffeine as effective, and caffeinated gum can be useful too because it is absorbed faster and may work well when taken closer to the start or during an event.
That leads to the next question. When should you take it?
If you are using capsules, tablets, or a measured drink, around 45 to 60 minutes before the key effort is a practical rule. That lines up reasonably well with how caffeine tends to rise in the blood. If you are using chewing gum, the effect can come on faster, which makes it a useful tool when you want something closer to the gun or later in the race when your soul is leaking out through your shoes.
For shorter races, like 5k through marathon, many runners will do well with a single pre race dose. For longer trail races, ultras, or anything where life starts to get weird after a few hours, splitting the dose often makes more sense. Rather than smashing 400 mg before the start and spending the first half of the race feeling like a haunted squirrel, it is often better to take a moderate pre race dose and then top up later with smaller amounts through gels, cola, chews, or gum. That approach can help preserve the upside while reducing the risk of gut revolt, anxiety, or a hideous late race crash.
And yes, we need to talk about the gut.
Because caffeine has an awkward side hustle as a bowel negotiator. It can stimulate the gut. It can increase the urge to defecate. It can combine magnificently with pre race nerves, concentrated gels, dodgy aid station choices, and poor pacing to produce what I will politely call an emergency bowel evacuation. There are runners who have had transcendent caffeine experiences. There are others who have seen God through a hedge while trying to get their shorts down in time.
That does not mean caffeine is bad. It means race day is not the day to improvise. Studies in runners show GI symptoms are common, and pre race feeding, sports products, and individual tolerance matter. Caffeine can clearly be one part of that broader gut equation, and emerging work also suggests it may worsen gut stress in some settings.
So the practical rule is simple. Practice your caffeine plan in training. Practice the exact product. Practice the exact timing. Practice it on a long run, on race intensity efforts, and ideally in circumstances that resemble race nerves and race breakfast. If your chosen plan turns your colon into an activist, that is useful information. Better to find that out near a familiar public toilet than at 3 am on a mountain ridge praying for shrubbery.
There is also the question of whether you need to “cycle off” caffeine before a race. Athletes love this stuff. They will happily turn one cup of coffee into a three week withdrawal strategy involving headaches, despair, and telling everyone they are “optimising receptor sensitivity.” The evidence here is not strong enough to say everyone needs a full withdrawal period. Habitual users can still gain performance benefits from caffeine. Some athletes may respond well to reducing intake slightly before a key race, but this is not mandatory and it is definitely not worth turning yourself into a miserable bastard all week if it ruins your mood and your sleep.
Speaking of sleep, caffeine can absolutely mess with it. That matters more than athletes often admit. A nice performance boost on Saturday afternoon is less exciting if it nukes Saturday night and leaves you half dead for the next few days. Recent reviews suggest caffeine supplementation can impair sleep in athletes, and larger doses taken later in the day are more problematic. So if your event starts at 4 pm, or you are using big late race doses in an overnight ultra, understand the trade off. Sometimes it is worth it. Sometimes it is a stupid own goal.
There is also individual variability. Some people do beautifully on caffeine. Some turn into trembling philosophers. Some get laser focus and smooth pacing. Some get reflux, panic, and a sudden interest in finding a portaloo. Genetics probably play some role, habitual intake probably matters a bit, sex differences may matter in some contexts, and product choice matters too. The main point is that the “best” dose is not the biggest dose you can survive. It is the smallest dose that gives you a meaningful benefit without wrecking your gut, your pacing, your brain, or your sleep.
So here is the practical bit. The bit athletes actually need.
If you are new to caffeine use in racing, start with about 2 to 3 mg per kg. That is enough to be useful for many runners and much less likely to end in chaos. Trial it before a key session or long run about 45 to 60 minutes before starting. Note how you feel. Note heart rate. Note perceived effort. Note whether your guts remain loyal.
If you already know you tolerate caffeine well, 3 to 6 mg per kg is the evidence based sweet spot for most performance use. You do not need to go higher. Ever. That heroic dose your mate swears by is probably either unnecessary or a cry for help.
If the event is long, consider splitting the dose. For example, a runner targeting 210 mg total might take 100 to 150 mg before the start, then smaller top ups later. That can work especially well in trail marathons, ultras, and late race scenarios where focus and perception of effort are falling apart.
If you want rapid delivery, caffeinated gum is a legit option. The research on gum is encouraging, including evidence of performance benefits and lower perceived effort, and the faster absorption profile makes it handy when timing is tight.
If you are racing late in the day, be conservative. The boost may be real, but so is the chance you spend the night staring at the ceiling feeling like a Victorian child who accidentally drank motor oil. Sleep still matters.
If you are prone to anxiety, reflux, palpitations, or gut issues, be even more conservative. Do not build your race plan around internet bravado. Build it around what your body actually tolerates.
And for the love of all that is decent, do not stack random caffeinated products without doing the maths. Athletes do this all the time. Coffee at breakfast. Caffeinated gel at the start. Cola at aid stations. “Focus” chew at halfway. Suddenly they are 500 mg deep and speaking fluent owl.
So, where do I land on caffeine in long distance running?
I like it. It works. It is one of the few legal supplements with a genuinely decent evidence base for endurance performance. It can reduce perceived effort, improve alertness, and help athletes maintain output when fatigue starts asking serious questions. But it only works well when it is used strategically. The line between performance aid and self inflicted disaster is not that wide.
Use enough, not too much. Time it properly. Practice it in training. Respect your gut. Respect your sleep. And remember that the goal is not to feel like an immortal warlord on the start line. The goal is to run well all the way to the finish without having to perform an emergency bowel evacuation behind a gorse bush while your race dreams and dignity disappear together.
