Hydration Rate Calculator

Calculate your sweat rate and hydration needs from pre- and post-exercise weight. Determines how much fluid to drink per hour during exercise.

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Sweat Rate

48.0 oz/hr

Sweat Rate (mL/hr)1,420 mL/hr
Dehydration Level1.25%
Target Fluid Intake38.4 oz/hr

Sweat Rate vs Pre-Exercise Weight

View formula & how it works →

How Sweat Rate Is Calculated

Formula

Sweat Loss (oz) = Weight Lost (lbs) x 16 + Fluid Consumed (oz)

Sweat Rate = Sweat Loss / Exercise Duration (hours)

Each pound of weight lost during exercise represents about 16 oz (473 mL) of sweat.

Hydration Guidelines

  • Replace 80% of sweat losses during exercise.
  • Dehydration above 2% of body weight impairs performance.
  • Dehydration above 4% can be dangerous.

    • Factors Affecting Sweat Rate

  • Temperature and humidity
  • Exercise intensity
  • Body size
  • Fitness level (fitter athletes sweat more efficiently)
  • Genetics

    • Example Calculation

    Pre-exercise: 160 lbs. Post-exercise: 158 lbs. Drank 16 oz during 60 minutes.

    1. 01Weight lost = 160 - 158 = 2 lbs.
    2. 02Sweat loss = 2 x 16 + 16 = 48 oz.
    3. 03Sweat rate = 48 / 1 hr = 48 oz/hr (1420 mL/hr).
    4. 04Dehydration = 2 / 160 x 100 = 1.25%.
    5. 05Target fluid intake = 48 x 0.8 = 38.4 oz/hr.

    Frequently Asked Questions

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