Plan your fluid and sodium intake for endurance events. Recommendations are based on keeping cumulative sweat losses within 1-2% of starting body weight and science-based sodium replacement guidelines.
kg
lbs
From a sweat test. Avg ~920, range 460-1840.
Recommendations
| Fluid Intake | Sodium | |
|---|---|---|
| 1% Loss Target | -ml/hr | -mg/L
|
| 2% Loss Target | -ml/hr | -mg/L
|
Danger Zone Higher dehydration levels (3-6% loss) — not recommended
These levels of dehydration can significantly impair performance, thermoregulation, and cognitive function. Risk of heat illness increases substantially. Not recommended.
| Fluid Intake | Sodium | |
|---|---|---|
| 3% Loss | -ml/hr | -mg/L
|
| 4% Loss | -ml/hr | -mg/L
|
| 5% Loss | -ml/hr | -mg/L
|
| 6% Loss | -ml/hr | -mg/L
|
Event Summary
Total Sweat Loss
-
Total Sodium Lost
-
1% Target
Total Fluid
-
Sodium Replaced
-
2% Target
Total Fluid
-
Sodium Replaced
-
How it works:
Fluid intake is calculated to keep your cumulative fluid loss within the target percentage of body weight. Sodium recommendations follow exercise science guidelines based on your sweat sodium concentration, event duration, sweat rate, and fluid replacement percentage.
Fluid intake is calculated to keep your cumulative fluid loss within the target percentage of body weight. Sodium recommendations follow exercise science guidelines based on your sweat sodium concentration, event duration, sweat rate, and fluid replacement percentage.
Reference: McCubbin, A.J. Sodium intake for athletes before, during and after exercise: review and recommendations. Perform. Nutr. 1, 11 (2025). https://doi.org/10.1186/s44410-025-00011-9
⚠️ Disclaimer: This tool is for informational and educational purposes only. It is not medical advice and should not replace consultation with a qualified healthcare professional or sports dietitian. Individual needs vary significantly. The authors are not liable for any adverse effects or consequences resulting from the use of this information.