How does carbohydrate ingestion influence endurance performance during prolonged events?

• A. Carbohydrates are harmful during endurance.
• B. Maintains blood glucose, delays fatigue, and can improve time-to-exhaustion; typical intake 30–90 g/hour depending on tolerance.
• C. Only protein matters.
• D. Carbs speed up fatigue.

Answer: (B)

During prolonged endurance efforts, the body increasingly relies on circulating fuel as muscle and liver glycogen stores become limited. Ingesting carbohydrates during the event provides exogenous glucose, helping to keep blood glucose levels stable and supplying a readily available energy source for working muscles and the brain. This extra fuel slows the rate at which glycogen is depleted, can lower perceived effort, and often extends how long an athlete can sustain the pace—improving time-to-exhaustion in many cases. The typical guidance is to consume about 30–90 grams of carbohydrate per hour, with the exact amount depending on what an athlete tolerates and can absorb. Using a combination of carbohydrate sources can support absorption over a longer period, especially in longer events, allowing closer to the higher end of that range without GI distress.