Carbohydrate per hour

Carbohydrate per hour describes the amount of carbohydrate that an athlete consumes each hour during endurance training or competition. The hourly intake influences how much fuel is available for working muscles, how quickly carbohydrate stores are depleted and whether the athlete experiences gastrointestinal distress.

Practical recommendations for hourly carbohydrate intake

Consuming carbohydrate during prolonged exercise maintains blood glucose, spares liver glycogen and delays fatigue. Research shows that absorption of glucose through the sodium–glucose cotransporter (SGLT1) tops out at about 60 g per hour; adding fructose allows additional carbohydrate to be absorbed via the GLUT‑5 transporter. Athletes in events lasting one to two hours can often perform well with 30–60 g of carbohydrate per hour from glucose or maltodextrin. In longer events, intakes up to 90 g per hour using a ~2:1 glucose:fructose blend provide more exogenous carbohydrate and reduce reliance on muscle glycogen. Going above 90 g per hour does not consistently increase performance and raises the risk of gastrointestinal problems because absorption and oxidation become limited. Adequate fluid intake and sodium help with gastric emptying and intestinal absorption, while training the gut during workouts improves tolerance.

Hourly fueling strategies

Runners and cyclists often aim for around 30 g of carbohydrate (about one gel or a small bottle of sports drink) per hour in shorter races. For marathons or long rides, athletes may increase to 60 g per hour by using drinks or gels containing glucose and maltodextrin; this rate matches SGLT1 capacity and is generally well tolerated. Ultra-endurance athletes competing for several hours may consume 70–90 g per hour from a combination of maltodextrin and fructose sources such as energy chews and drink mixes, taking advantage of multiple transporters to increase oxidation. Athletes should experiment in training to determine their optimal intake and should not jump straight to high rates without practice. Lower intakes can also be used deliberately during easy sessions to promote fat utilization.

A measured approach to carbohydrate per hour helps athletes sustain intensity without overwhelming their digestive system. Adjusting intake based on event duration, environmental conditions and personal tolerance maximizes the benefits of carbohydrate fueling and complements strategies such as carbohydrate periodization and multi-transportable carbohydrate blends.

Related Terms: Glucose:fructose ratio, Gastric emptying, Intestinal absorption, Carbohydrate periodization, Palatability