Hydration guidelines

Drink steadily through the day, and adjust fluid intake for exercise, sweat loss, heat, and sauna use.

• Daily baseline: Aim for about 8 oz (240 ml) of fluid per hour during the first 10 hours after waking—roughly 80 oz (2.36 L) total. 1
• Rough daily guideline: Half your body weight in pounds, in ounces of fluid, is a loose starting point for daily intake; it does not include extra fluid lost through exercise or sauna use. 2
• During and after exercise: During exercise, use body weight in pounds divided by 30 to estimate ounces every 15–20 minutes, sipping steadily as practical. Afterward, replace about 125%–150% of the weight lost with fluid. 3 4
• Heat, heavy sweating, and sauna: Increase exercise-fluid estimates by about 50%–100% in heat or with heavy sweating. In a hot sauna, drink at least 8–16 oz (240–480 ml) per 20–30 minutes. 5
• Timing and food: Get more fluids earlier in the day; in the three hours before sleep, limit intake to sipping as needed. Water-rich foods such as watermelon also contribute to hydration. 6 7
• Electrolytes: With substantial sweating or exercise, consider fluids containing electrolytes such as sodium, potassium, and magnesium. 8