A rough guide to how much fluid you lose and roughly how many calories you burn during an infrared sauna session, so you know how much to rehydrate.
Around 16 stone is 102 kg, 12 stone is 76 kg, 10 stone is 64 kg.
How this works
Sweat is estimated from a typical sweat rate per minute, scaled up or down by the intensity you pick. As a rule of thumb 1 litre of sweat weighs about 1 kg, so the fluid figure is also roughly the weight you lose during a session. That weight is water, not fat, and comes straight back once you rehydrate.
Calories are estimated from your resting metabolic rate raised by a modest factor while your body works to cool itself. Heat alone burns far fewer calories than exercise, so the number stays sensible rather than the inflated claims you sometimes see.
Assumptions: these are population averages and individuals vary a lot. The figures are a guide for hydration and expectation, not a medical or fitness measurement. Drink water before, during and after, and stop if you feel unwell.