Carbohydrates per hour
Carbohydrates per hour is the measure of your fuelling during exercise: how much fast energy you take in along the way, in grams per hour. On longer or harder sessions it helps decide whether you stay upright or run empty.
Why carbohydrates during exercise?
Your body stores only a limited supply of carbohydrate (glycogen) — enough for roughly one and a half to two hours of hard effort. When that supply runs empty, your output drops (the well-known "bonk"). By topping up carbohydrates along the way, you spare your supply and hold your pace for longer.
For short or easy sessions, topping up usually isn’t needed; there you get by on your supply and a normal daily intake. Fuelling during the session only becomes important as the duration climbs or the intensity stays high.
How much, and how do you build it up?
Common guidelines scale with duration. Up to about an hour you need nothing. For efforts of one to two and a half hours, roughly 30 to 60 grams per hour is worthwhile. Beyond that the advice climbs to 60 to 90 grams per hour — and the top of that range is only achievable with a mix of carbohydrate sources (glucose and fructose) and a trained gut, because otherwise your gut can’t keep up with the uptake.
The biggest pitfall is your stomach. High intakes need a trained gut: build them up gradually in training and test your race nutrition beforehand, never for the first time on the day itself. What you tolerate is personal — start conservatively and scale up what works.
How Trimetra personalises this
Trimetra tunes the fuelling advice per session to that session’s duration, intensity and sport, and takes into account what you’re used to tolerating instead of prescribing one universal number. So you get different advice for a long, hard ride than for a short endurance run — and you build up higher intakes step by step.
Frequently asked questions
How many carbs do you need per hour?
That scales with duration and intensity: up to about an hour you need nothing, for one to two and a half hours roughly 30 to 60 grams per hour is worthwhile, and beyond that the advice climbs to 60 to 90 grams per hour. The top end is only feasible with a mix of glucose and fructose and a trained gut — start conservative and build up.
What is bonking (hitting the wall)?
The moment your carbohydrate store (glycogen) runs out and your power collapses — usually after roughly one and a half to two hours of solid effort without refuelling. You prevent it by taking in carbs along the way, sparing your store.
How do you train your gut for more carbs?
By building up higher intakes gradually in normal training sessions, so your stomach and gut get used to them. Always test your race nutrition beforehand in training — never for the first time on the day itself. What you tolerate is personal.
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