Loading page
About this tool
Before, during and after fluid plan for heated yoga, from a measured weigh-in sweat rate or your room temperature and class style.
This calculator turns a hot yoga class into a fluid plan: how much to drink in the hours before, how much to sip during, and how much to replace afterwards. It uses the sweat-rate equation from the ACSM Position Stand on Exercise and Fluid Replacement — sweat loss equals pre-class weight minus post-class weight plus anything drunk — and applies the same guideline's targets of 5-7 mL per kg beforehand, keeping body-mass loss under 2%, and replacing 125-150% of any remaining deficit. If you have not weighed yourself, it will model a sweat rate from room temperature, humidity, class style and body size instead.
Open Hot Yoga Hydration Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Weigh-in mode gives your real sweat rate instead of a population average.
Separates prehydration, in-class sips and post-class replacement so nothing is drunk all at once.
Estimates sweat sodium at roughly 1,150 mg per litre so you know when water alone is not enough.
About 5-7 mL per kilogram of body weight roughly four hours before class — that is 350-490 mL for a 70 kg person. If you produce no urine in that window or it is dark, the ACSM suggests a further 3-5 mL/kg about two hours before.
Commonly 1.0-1.5 litres in a 90-minute heated class, which is a sweat rate near 0.7-1.0 L per hour. It varies widely with room temperature, humidity, body size and fitness, so weighing yourself before and after is the only reliable way to know your own figure.
Weigh yourself undressed before class and again afterwards towelled dry, then add whatever you drank: sweat loss in litres equals the weight drop in kilograms plus the fluid drunk in litres. Divide by class length in hours for a rate in litres per hour.
Water is usually enough below about a litre of sweat loss. Past that you are also losing roughly 1,150 mg of sodium per litre, and replacing large volumes with plain water can dilute blood sodium — add salt through food or an electrolyte drink. This is general information; anyone with kidney, heart or blood-pressure conditions should ask their doctor.
Add the Hot Yoga Hydration Calculatorwidget to your blog or website — free, responsive, no signup. Just keep the “Widget by AltFTool” credit link visible.
<iframe src="https://www.altftool.com/embed/widget/hot-yoga-hydration-calculator"
title="Hot Yoga Hydration Calculator — free AltFTool widget"
width="100%" height="640" style="border:0;border-radius:12px;overflow:hidden"
loading="lazy" referrerpolicy="no-referrer-when-downgrade"></iframe>
<p style="font-size:12px;margin:4px 0 0">Widget by <a href="https://www.altftool.com/tools/all/hot-yoga-hydration-calculator?utm_source=embed&utm_medium=widget">AltFTool — free online tools</a></p>