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Rehydration Tips

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    How to Use the Hydration Calculator

    The Hydration Calculator estimates fluid loss during swimming based on body weight, swim duration, intensity, pool temperature, and humidity, providing tailored rehydration strategies.

    Estimating Fluid Loss

    Enter your body weight, swim duration, intensity, pool temperature, and humidity. The calculator estimates fluid loss and recommends rehydration volume and electrolyte intake.

    Example: 70kg swimmer, 1-hour moderate swim at 28°C, 60% humidity → Fluid Loss ≈ 0.7-1.0L, Rehydration ≈ 1.0-1.5L.

    Environmental Factors

    Higher pool temperatures and lower humidity increase fluid loss. Adjust inputs to reflect your training conditions.

    Stay hydrated to optimize performance. Learn more about hydration with USA Swimming’s Hydration Tips.

    Hydration Calculation Formulas

    Understand the math behind fluid loss and rehydration:

    Fluid Loss Calculation

    Fluid Loss (L/hr) = Base Rate × Weight Factor × Intensity Factor × Environment Factor

    Base rate: 0.5-1.0 L/hr (adjusted for swimming). Weight factor: ~0.015 L/kg/hr. Intensity factor: Low (0.8), Moderate (1.0), High (1.2). Environment factor: Adjusted for temperature and humidity.

    Rehydration Recommendation

    Rehydration Volume (L) = Fluid Loss × 1.5

    Replaces 150% of fluid lost to account for urine loss and ensure full hydration.

    Electrolyte Recommendation

    Sodium (mg) = Fluid Loss (L) × 500-1000 mg/L

    Estimates sodium loss based on typical sweat composition in swimming.

    Frequently Asked Questions

    Why is hydration important for swimmers?
    Dehydration impairs performance, reduces endurance, and increases fatigue, even in water.
    How does swimming affect fluid loss?
    Swimmers lose fluid through sweat and respiration, though less than land sports due to water cooling.
    What fluids should I use for rehydration?
    Water for short sessions; electrolyte drinks (sodium, potassium) for longer or intense sessions.
    How does pool temperature affect hydration?
    Warm pools (above 28°C) increase sweat rate, requiring more fluid intake.
    Can I use this for open water swimming?
    Yes, but adjust for higher sweat rates due to sun exposure and no pool cooling effect.