Electrolyte Balance Calculator
Estimate sodium and fluid losses from sweating to maintain electrolyte balance during exercise. Calculate sweat rate and electrolyte replacement needs for athletes and active individuals.
Formula & Reference
| Variable | Symbol | Formula | Units |
|---|---|---|---|
| Electrolyte Balance Calculator | — | Sweat Rate = (Pre-weight - Post-weight + Fluid Intake) / Time | mL/hour |
Step-by-Step Examples
160 lbs pre, 158 lbs post, drank 16oz, exercised 1.5 hours.
- Weight loss: 2 lbs × 16oz/lb = 32oz
- Total fluid loss: 32 + 16 = 48oz
- Sweat rate: 48/1.5 = 32 oz/hr = ~946 mL/hr
- Moderate-to-high sweat rate
170 lbs pre, 166 lbs post, drank 24oz, exercised 2 hours.
- Weight loss: 4 lbs = 64oz
- Total loss: 64+24 = 88oz
- Sweat rate: 88/2 = 44 oz/hr = ~1300 mL/hr
- Very high sweat rate — needs aggressive replacement
150 lbs pre, 149.5 lbs post, drank 8oz, exercised 1 hour.
- Weight loss: 0.5 lbs = 8oz
- Total loss: 8+8 = 16oz
- Sweat rate: 16 oz/hr = ~473 mL/hr
- Light-to-moderate sweat rate
Real-World Applications
Common Mistakes to Avoid
Pure water replacement without electrolytes during prolonged heavy sweating can cause hyponatremia (low blood sodium) — a serious condition.
Sweat rates vary 10x between individuals (0.5-2.5+ L/hour) based on fitness, heat acclimation, and genetics. Test your own rate, don't use generic averages.
Drinking excessive water before exercise doesn't prevent dehydration and can dilute sodium levels. Hydrate steadily in the hours before, not all at once.