Individual Hydration Requirements
Hydration needs vary based on body size, sweat rate, environmental temperature, and exercise intensity. Calculate sweat rate by weighing yourself before and after one hour of exercise; each pound lost equals 16 ounces of fluid.
Baseline Daily Hydration
Most people require half their body weight in ounces of water daily. Athletes add 16-24 ounces for every hour of exercise. Someone weighing 180 pounds needs 90 ounces baseline, plus additional amounts for activity.
Pre-Exercise Hydration
Begin workouts well-hydrated, not desperately trying to catch up before starting. Drink 400-600 mL (14-20 oz) of fluid two hours before exercise, then 200-300 mL (7-10 oz) 20 minutes before.
During-Exercise Drinking
For exercise under 60 minutes, water suffices. Beyond 60 minutes, add carbohydrates (4-8% carbohydrate solution) and electrolytes. Aim for 150-250 mL (5-8 oz) every 15-20 minutes.
Electrolyte Considerations
Sodium, potassium, magnesium, and calcium drive muscle function and fluid retention. Sweat contains primarily sodium. Sports drinks with 300-600 mg sodium per liter improve fluid retention and performance.
Post-Exercise Rehydration
Drink 150% of fluid lost during exercise over four hours post-exercise. If you lost two pounds, drink 48 ounces over the following four hours. Include sodium to enhance fluid retention.
Hyponatremia Risk
Excessive water without electrolytes, particularly during extended exercise like marathons, can dangerously dilute blood sodium. Include electrolytes in longer endurance efforts and recovery fluids.
Practical Hydration Plan
Drink consistently throughout the day. Establish routine: water with breakfast, hydration during training, electrolyte drink post-exercise. Monitor urine color—pale indicates adequate hydration; dark indicates insufficient intake.