How many carbs per hour when running?

How many carbs per hour?

The benchmark depends mostly on duration. Up to 1 hour, water is usually enough. Between 1 and 2 hours, aim for 30 to 60 g/h. Beyond 2 hours and in competition, 60 to 90 g/h become worthwhile, and trained runners can target 90-120 g/h. As soon as you go past 60 g/h, switch to glucose + fructose products (about 1:0.8 ratio) to use both absorption pathways. Spread the intake steadily rather than in one big hit.

Training your gut (8-12 weeks)

Tolerating 80 or 90 g/h isn't improvised: it's trained, like a muscle. Over an 8 to 12-week block, gradually raise the carbs you take on your weekly long runs — start at 40-50 g/h, then add 5 to 10 g every two weeks. This "gut training" increases transporter density and improves comfort. Use the products and concentrations you'll race with in training.

Your benchmarks

• Under 1 h: water; 1-2 h: 30-60 g/h; over 2 h: 60-90 g/h
• Glucose + fructose products from 60 g/h
• 8-12-week gut-training block before the goal
• Intake spread every 20-30 minutes
• Concentration and products validated in training

Common mistakes

• Aiming for 90 g/h in a race without ever training it
• Using a single-source product (glucose only) beyond 60 g/h
• Taking it all at once rather than steadily
• Ramping up too fast and triggering GI issues
• Copying another runner's number without accounting for your own tolerance

FAQ

Related articles