Health & Fitness
Hydration After Exercise Calculator
Estimate fluid to drink after exercise from weight lost during the session.
This result is the amount of fluid to drink after the session, spread over the next few hours rather than all at once.
Formula
Post-exercise fluid is about 1.5 litres for each kilogram of body weight lost during exercise.
How it works
Weight lost is mostly sweat, and the 1.5 multiplier allows for continued sweating and urine losses after you stop. Weighing before and after gives the loss figure.
Worked example
For example, losing 1 kilogram during a 60-minute session gives 1 × 1.5 = 1.50 litres to drink after the session, spread over the next few hours.
FAQs
Why 1.5 and not 1.0?
Because you keep losing fluid after exercise, so replacing exactly what was lost is not quite enough.
Do I need sports drinks?
For sessions over about an hour, or heavy sweating, electrolytes help; water suits shorter sessions.
Should I drink it all at once?
No. Spread it over a few hours.
General information only, not medical advice.
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