Hydration Science
Proper hydration is essential for athletic performance, thermoregulation, and preventing dehydration-related illness. The formula used here starts with a baseline of 35 ml per kg of body weight, then adds activity-specific fluid needs based on intensity and duration.
Total Fluid = (35 × weight_kg) + (duration_min × intensity_factor) + heat_adjustment + humidity_adjustment
Intensity Factors
- Low: 5 ml/min (walking, light cardio)
- Moderate: 10 ml/min (steady running, cycling)
- High: 15 ml/min (tempo, interval work)
- Extreme: 20 ml/min (sprint, all-out effort)
Heat & Humidity Adjustments
- Temperature above 25°C: +25% fluid needs
- Temperature above 30°C: +50% fluid needs
- Humidity above 60%: +15% fluid needs (impairs sweat evaporation)
Electrolyte Recommendations
For activities longer than 60 minutes, consuming electrolytes (especially sodium) helps maintain fluid balance and delays fatigue. Sodium aids fluid absorption and retention. A typical target is 300–600 mg sodium per hour and 150–300 mg potassium per hour.