Carbs, sodium and caffeine for race day, with a timeline that tells you when to take each one. Sized for running in the heat.
A trained runner stores enough glycogen for roughly 90 minutes to two hours of hard running. Everything after that is paid for by what you eat while moving. This is why marathons fall apart at 30 kilometres rather than gradually, and why the runner who overtakes you at 35 is rarely fitter than you, only better fed. Fuelling is the one part of race performance you can fix in a fortnight.
The most common mistake is waiting. Absorption takes time, and once blood is diverted to working muscle your gut gets slower, not faster. A runner who starts fuelling at 45 minutes and keeps a rhythm will finish stronger than one who takes the same total amount starting at two hours. Set an alarm on your watch if you need to, because you will forget.
Carbohydrate needs are much the same anywhere. Sodium is not. You sweat more here, for longer, in most races of the year, and replacing litres of that with plain water alone is how runners end up nauseous, bloated and slow late in a long event. If you are out for more than two hours in Malaysian conditions, sodium is not an optional extra.
Every gel brand, salt product and sports drink behaves differently in a running stomach. Test each one on a long run at race effort, not on an easy jog where anything works. If a race provides a drink you have never tried, either practise with it beforehand or carry your own and use the tables for water only.
For anything under an hour, none. Between one and two hours, 30 to 60 grams an hour is plenty. Beyond two hours, 60 to 90 grams an hour is the working range, and trained guts can take more. The number matters less than taking it steadily from early on rather than waiting until you feel empty, because once you are empty it is too late to catch up.
Because absorbing 90 grams of carbohydrate an hour while running hard is a skill, not a given. The transporters that move sugar out of your intestine increase with repeated exposure. Runners who take their race carb load in training for six to eight weeks tolerate amounts that would make an untrained runner ill. If you have not practised it, the tool caps your target lower on purpose.
More than a plan written for a European autumn assumes. Sweat sodium concentration varies enormously between people, roughly 300 to 2000 mg per litre, and you will sweat more litres here. The range this tool gives assumes a typical concentration. If you finish runs with white salt crust on your face and cap, you are on the high end and should aim past the top of the range.
It works, and it is one of the few legal aids with strong evidence behind it. Three to six milligrams per kilogram of body weight, taken 45 to 60 minutes before the start, is the usual dose. If you drink coffee daily you already have some tolerance and sit at the higher end. Do not try it for the first time on race day, and do not stack a pre-race dose with three caffeinated gels unless you have practised that exact combination.
One to four grams of carbohydrate per kilogram of body weight, three to four hours before the start, made of food you have eaten before many times. Low fibre, low fat, nothing new. The purpose of race morning breakfast is to top up liver glycogen, not to be interesting.
Work backwards from the plan. Count the gels, check what the race provides on course and at which kilometre, and carry the difference. Malaysian races vary a lot in what is on the tables, so read the race pack rather than assuming. If the numbers add up to more than you can carry, plan to take the on-course sports drink and count its carbohydrate towards your hourly total.
Turn any distance and finish time into pace per km, pace per mile and speed.
Open tool →Break a goal finish time into every kilometre split, ready to print.
Open tool →Predict your finish time at another distance from one recent race result.
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