Hydration for Exercise
What sports bodies advise about drinking during exercise, and how our calculator models training time.
Baseline + Exercise Add‑ons
The American College of Sports Medicine (ACSM) recommends an individualized drinking plan during exercise that prevents excessive dehydration (generally defined as >2% body mass loss) and avoids overdrinking that leads to weight gain (ACSM Position Stand, 2007).
ACSM advises determining sweat rate (e.g., by weighing before/after a representative workout) and matching intake accordingly; sodium should be replaced during prolonged, heavy sweating (ACSM, 2007).
Our calculator adds water with exercise time as a heuristic to give a practical starting point. It is not a substitute for measuring your own sweat rate or following medical advice.
Signs to Watch
ACSM notes that thirst, urine color, and body mass change provide practical cues; aim to keep body mass loss <2% and avoid weight gain (ACSM, 2007).
Use the Calculator
Example (calculator): weight 70 kg, age 25, exercise 1 h, 2500 kcal, climate: temperate. → Total need: 3650 ml (123 oz, 15 cups); from pure water: 3210 ml (109 oz, 13 cups); from food: 440 ml (15 oz, 2 cups). This text reflects the calculator's current logic.
For individualized plans for competitive sport, follow ACSM guidance and your clinician’s advice.
Sources
- ACSM Position Stand: Exercise and Fluid Replacement (2007)Individualized plan; avoid >2% body mass loss and overdrinking; replace sodium during prolonged heavy sweating