Home▸Medicine & Biophysics▸Sweat Rate & Electrolyte Loss Calculator

💧 Sweat Rate & Electrolyte Loss Calculator

Calculate sweat rate, percent body-mass loss and sweat sodium loss from your own pre/post-exercise weights, then see ACSM-guideline rehydration volume on a live dehydration-risk gauge.

Medicine & Biophysics2DEasy60 FPS

This calculator applies the standard ACSM (American College of Sports Medicine) sweat-testing method: it turns pre- and post-exercise body weight, fluid intake and urine output into a real sweat rate in litres per hour, a percent body-mass loss reading flagged against the 2% threshold known to measurably impair endurance performance, and an estimated sweat sodium loss based on your chosen sweat-salt concentration.

🔬 What It Demonstrates

🎮 How to Use

Adjust the pre- and post-exercise weight sliders to set your body-mass loss, then add any fluid you drank and urine you passed during the session so the sweat-volume calculation nets those out correctly. Pick a sweat-salt category, light, average, or heavy "salty sweater", to convert sweat volume into milligrams of sodium lost, and watch the gauges update live against the 2% dehydration-risk line and a typical single-serving electrolyte drink's sodium content.

💡 Did You Know?

Did you know that losing just 2% of body mass as sweat, only 1.4 kilograms for a 70-kilogram athlete, is enough to measurably reduce endurance performance according to ACSM fluid replacement guidelines? Because sweat sodium concentration varies roughly fourfold between individuals, two athletes who lose identical sweat volumes can need very different amounts of electrolyte replacement.

⚙ Under the hood

Calculate sweat rate, percent body-mass loss and sweat sodium loss from your own pre/post-exercise weights, then see ACSM-guideline rehydration volume on a live dehydration-risk gauge.

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2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install