Sweat rate.
Weigh in, train for an hour, weigh out. The scale knows how much you sweat better than any app does. Then plan the fluids for race day around your own number.
0litres per hour
Your sweat rate
Saved in this browser only.
Fluid plan for your event
| Hour | Fluid | Splashdown |
|---|
Saved sessions
Test in different weather and you will see how much the number moves. Hot and humid days are the ones that matter.
| Date | Session | Conditions | L/h | Body mass change | Delete |
|---|
Plain cautions
- Do not plan to drink more than you sweat. Gaining weight over a session means you drank too much, and over-drinking carries its own risk (low blood sodium).
- The plan keeps body-mass loss under about 2%, the level the American College of Sports Medicine uses as the line for performance.
- One test is one day. Sweat rate changes with heat, humidity, pace and fitness. Retest when the season changes.
- This is a training calculator, not medical advice. If you have a heart, kidney or blood pressure condition, ask your doctor how much to drink.
Source: Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Med Sci Sports Exerc 2007;39(2):377-90. The formula: (weight before minus weight after, plus fluid drunk, minus urine) divided by hours, with 1 kg of mass lost counted as 1 L of sweat.