Hydration: how much you need and how it affects performance

Water helps transport nutrients, regulate temperature, and support muscle contraction. Dehydration equal to about 2% of body weight can impair physical and mental performance.

How much should you drink?

A practical starting point is about half an ounce per pound of body weight daily, or roughly 2.4 liters for a 154-pound person. Add 17 to 34 ounces per hour of exercise, adjusting for heat and sweat rate.

Signs you are on track

• Pale yellow urine through most of the day.
• No persistent thirst.
• Only a small weight change across a workout.

What about electrolytes?

Water is generally enough for workouts under an hour. Longer sessions, intense heat, or very salty sweat may call for sodium and potassium replacement.

Do coffee and tea count?

Yes. The diuretic effect of moderate caffeine is small, so these drinks still contribute to daily fluid intake.