Water intake

Aim for about 8 oz (240 ml) of fluid per hour during the first 10 hours after waking, adjusting for exercise, sweating, heat, and thirst. 1

• Daily total: That’s roughly 80 oz (about 2.4 liters) over those 10 hours. A separate rough daily guideline is half your body weight in pounds, in ounces—for example, about 100 oz at 200 lb. 2 3
• During exercise: Use the Galpin equation: body weight in pounds ÷ 30 = ounces every 15–20 minutes. 4
• Heavy sweating or heat: Increase the exercise amount by 50%–100%. If you feel parched, a rough guide is 16 oz (about 500 ml) per hour while you’re thirsty. 5 6
• Replace losses and consider electrolytes: After exercise, replace about 125%–150% of the fluid lost. Electrolytes may be useful when sweating heavily or exercising; Huberman also recommends them with fluid when consuming caffeine. 7 8 9