💧 Hydration Needs Calculator

Calculate fluid & electrolyte requirements based on sweat rate and sodium loss to prevent dehydration or hyponatremia

Body Weight (kg)

Exercise Duration (minutes)

Sweat Rate (ml/hour) Average: 500-1000 ml/h (moderate exercise), 1000-2000 ml/h (intense)

Sodium Concentration in Sweat (mg/L) Average: 500-700 (low), 700-900 (moderate), 900+ (salty sweater)

Climate Conditions Moderate (20-25°C/68-77°F) Hot (25-30°C/77-86°F) Very Hot (>30°C/86°F) Cool (10-20°C/50-68°F) Cold (<10°C/50°F)

📊 Your Hydration Needs

💦 Water Replacement

0

ml per hour

0 total for session

🧂 Sodium Replacement

0

mg per hour

0 total for session

Recommendation: -

ℹ️ How to Use This Calculator & Example Values ▼

📝 Instructions & Examples:

• Sweat Rate: Measure by weighing yourself before/after exercise (1kg lost ≈ 1L sweat)
• Sodium Concentration: Average is 800mg/L (salty sweaters may lose 1000+ mg/L)
• Climate Factor: Hotter conditions increase needs by 20-50%

🏃 Example Calculation:

70kg athlete in hot climate:

• Duration: 90 minutes
• Sweat Rate: 1000 ml/hour
• Sodium Loss: 900 mg/L
• Results:
  • Water: 1200 ml/hour (1800 ml total)
  • Sodium: 1080 mg/hour (1620 mg total)

⚠️ Hyponatremia Warning Signs:

Headache, nausea, confusion, seizures (from overhydration without electrolytes)