What is the role of hydration in exercise performance, and how much fluid should an average adult consume before and during exercise?

• A. Hydration maintains plasma volume and temperature regulation; about 500 ml 2–3 hours before, and 200–300 ml every 15–20 minutes during; adjust for sweat rate
• B. Hydration has no impact on performance; drink only after exercise
• C. Hydration should be avoided before exercise to prevent bloating
• D. Hydration is only important for endurance events and not for strength training

Answer: (B)

Hydration helps keep blood volume and body temperature in a range that supports steady performance. When you sweat, you lose fluids (and electrolytes), and maintaining fluid intake during exercise helps preserve cardiovascular function, keep core temperature down, and maintain cognitive and physical performance. For an average adult, a practical approach is to start well-hydrated, about 500 ml (roughly 16–17 oz) 2–3 hours before exercise, and then replace fluids during the session with about 200–300 ml (7–10 oz) every 15–20 minutes, adjusting for how much you sweat and the environment. If you’re exercising longer or in heat, you may need more and may benefit from electrolytes. Drinking only after exercise misses the opportunity to protect performance during activity.