Caffeine Protocols for Race Day

An espresso in transition at an IRONMAN. A 200 mg tablet in the bottle on a half. A caffeine gel at 30 km of the marathon. Most age-groupers take caffeine on instinct and without a plan. The International Society of Sports Nutrition says what a run of recent meta-analyses says: caffeine works, but only if it is dosed like a drug, against body weight, a clock and some knowledge of how the athlete responds.

The short version: 3 to 6 mg per kg of body weight, 45 to 60 minutes before the start, with an expected performance gain of 2 to 4% in efforts lasting more than five minutes. That is the ISSN position from 2021, and the research since has held the same range.

How caffeine works, in one paragraph

Caffeine blocks the A1 and A2A adenosine receptors in the brain. Adenosine builds up during exercise and signals fatigue. Fewer signals reaching the brain means less sense of having had enough. This is not a boost in any literal way, because caffeine does nothing to the muscles. It turns down the volume on fatigue in the head.

There is a second floor to it: higher motor cortex excitability, better motor unit recruitment, dopamine modulation. The athlete wants to push, and the brain allows more of it.

How much, when and in what form

Dose

No magic here: 3 to 6 mg of caffeine per kilogram of body weight. For a 75 kg athlete that is 225 to 450 mg. For a 60 kg athlete, 180 to 360 mg.

Reference points:

Double espresso, around 130 mg
Cup of filter coffee, around 95 mg
Standard caffeine gel, 25 to 100 mg depending on the brand
Caffeine tablet, 100 or 200 mg

For most age-groupers, 3 mg/kg is an excellent starting point. Above 6 mg/kg the risk of side effects climbs quickly, tachycardia, gut trouble, the shakes, while the benefit does not. At 9 mg/kg it is a gamble rather than a strategy.

Timing

Caffeine peaks in the blood 45 to 60 minutes after it is taken. The half-life is three to six hours. So in a sprint or an Olympic distance, the whole dose goes in 45 minutes before the gun. At 70.3 and IRONMAN it makes more sense to split it into a starting dose plus a top-up two to three hours into the race, for example a caffeine gel on the second half of the bike and another halfway through the run.

Over the Olympic distance, the interesting studies use 6 mg/kg taken 45 to 60 minutes before the start. The measured improvement in finish time ran to tens of seconds. In a race where the podium is decided by seconds, that is currency.

Form

Tablet, coffee, gel or gum, blood caffeine concentration ends up in much the same place. Gum is absorbed through the lining of the mouth and acts faster, with an effect in 10 to 15 minutes, which suits a mid-race top-up. Caffeinated carbohydrate gels such as Maurten Caf 100 and GU Roctane act more slowly, but they deliver the caffeine alongside carbohydrate at the moment it is needed.

Who gains nothing from it

Some athletes feel no clear ergogenic benefit from caffeine at all, and the studies put that share anywhere from the low tens to several tens of percent. The reason is genetic: a variant of the CYP1A2 gene decides whether caffeine is metabolised fast or slow. Slow metabolisers get side effects more often, palpitations and gut trouble, and less of the benefit.

The second problem is tolerance. Three espressos a day for five years and the body has adapted. A week off caffeine before an important race improves the odds that the race-day dose does what it should. Some go further and run a seven to ten day washout.

The third is gut stress. In triathlon the stomach is the most common cause of a race falling apart, especially over long distance. An athlete who has never tested caffeine under load in training should not be putting a 200 mg tablet in the bottle for a first race. Test it in a race-intensity session first, always.

The side effects

The common ones:

Tachycardia and shaking hands at doses above 6 mg/kg
Anxiety and trouble concentrating in sensitive individuals
Diarrhoea and stomach cramps, particularly alongside a heavy carbohydrate load from gels
Worse sleep, since caffeine taken on a run that finishes in the late afternoon can interfere with recovery

The practical conclusion: write the caffeine dosing into the race plan the way a carbohydrate gel gets written in. Hour, dose, form. No improvising.

A protocol to copy

A simple, tested scheme that can go into the next simulation session.

Sprint and Olympic distance:

The day before: keep caffeine to a minimum, one coffee in the morning at most
45 to 60 minutes before the start: 3 mg/kg as coffee or a tablet
During: nothing

70.3:

The week before: cut back to one coffee a day
45 minutes before the start: 3 mg/kg
After 90 minutes of racing: a caffeine gel, 50 to 75 mg
Halfway through the run: optionally a second caffeine gel

IRONMAN:

The week before: reduce daily caffeine
45 minutes before: 2 to 3 mg/kg
Every two hours: a top-up of 50 to 100 mg, as a gel, capsule or caffeinated salt
Total race dose: 6 to 8 mg/kg spread across nine hours or more

Before you start

The dose has to have been tested in training at race intensity. If it has not, leave caffeine for the next race and run this one without it. The risk of the stomach shutting down or the heart going haywire is real. March, April and early May are the point in the season to test a protocol. Not June, with a year of work riding on the result.

This sits alongside Running in the Heat: How Not to Blow Up on Race Day. Racelify lists triathlons worldwide by date and distance.