During prolonged exercise, what is a commonly recommended hydration guideline?

• A. 2-3 liters per hour without electrolytes
• B. 500-1000 ml every 2 hours
• C. 400-800 ml per hour with electrolytes as needed
• D. Drink only when thirsty, avoiding scheduled intake

Answer: (C)

Maintaining fluid balance and electrolyte replacement is essential during prolonged exercise. The best guideline is about 400–800 ml of fluid per hour, with electrolytes included as needed to match what you sweat. Electrolytes, especially sodium, help preserve plasma volume and improve fluid absorption, which supports performance and reduces the risk of cramps and hyponatremia in long sessions. Sip regularly in small amounts (roughly every 15–20 minutes) rather than gulping large volumes, to keep the gut comfortable and absorption steady. This range is adaptable to individual sweat rates and conditions; some athletes may need more, others less, but this amount covers most scenarios. Relying on thirst alone isn’t ideal for long-duration exercise because thirst can lag behind actual dehydration and performance can suffer. Conversely, drinking 2–3 liters per hour is typically excessive for most people and can cause GI distress, while spacing intake to only every few hours risks dehydration. The combination of moderate hourly intake with electrolytes as needed best aligns with how the body handles fluids and salts during extended activity.