How much sodium and water do you need per hour? Trail running calculator
Work out your sodium per hour, your water needs and your cramp risk for your next trail race. Complete the 3 steps and get a personalised hour-by-hour plan.
As a rough guide, long races usually call for 300-600 mg of sodium per hour, and up to around 1,000 mg/h if you sweat very salty in hot weather. The calculator adjusts that figure to your profile.
Orientative estimator based on ACSM/ISSN guidelines. Not a personalized plan. Consult a sports nutrition professional for individual advice.
Your profile
If your clothes get a white crust after training, you are a salty sweater.
History and habits
Your personalized hydration plan
Hour-by-hour hydration plan
Based on ACSM guidelines. Individual needs may vary.
| Hour | Water | Sodium | What to take |
|---|
Your sodium dose: how to cover it
Based on your profile you need about mg of sodium per hour. These are the salt tablets and capsules that cover it best, picked from our comparison:
Most Sodium per Capsule (and Anti-Doping Certified)Crown Sport Nutrition Pro Salt CapsView on Amazon(opens in a new tab)
Best for Moderate Sweaters226ERS Salts ElectrolytesView on Amazon(opens in a new tab)
Best for Heavy Salty SweatersPrecision Fuel & Hydration PH 1500View on Amazon(opens in a new tab)Rough estimate. More sodium is not always better: if you have high blood pressure or kidney or heart problems, check with a healthcare professional first.
Pre-race hydration (ACSM)
Drink 5-10 ml per kg of body weight, 2-4 hours before the start.
How will you carry all that water?
For a race this long you need a 5 L vest with room for your water and mandatory gear:
For a race this long you need a 8-10 L vest with room for your water and mandatory gear:
For a race this long you need a 10-12 L vest with room for your water and mandatory gear:
For a race this long you need a 12-15 L vest with room for your water and mandatory gear:
Recommended electrolyte products
The most popular electrolyte products used in trail running and ultra races.
Compare all salt tablets and sodium capsules →
