How to estimate the volume a person sweats?
I'm pretty comfortable with my technique to stay hydrated, but I am curious about estimating how much liquid is actually involved. I generally am just concerned with getting rid of it, but occasionally (especially when drips become a steady trickle) I wonder at how much I can make.
I guess if I weighed the easier outputs and inputs and did calorie math to account for my breath I could get something, but that sounds like a lot of (unappealing) work.
Weighing clothes twice might give me a lower bound, but working in plastic wrap (to avoid drip and evaporation loses) isn't pleasant.
Is there a casual way to estimate sweat? Preferably usable in the field with minimal prep-work.
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You basically have it, the formula is
Your Weight at start
- Your Weight at end
+ Weight of water consumed
- Weight of water urinated
---------------------------
= Water lost via sweat
Then you divide the water lost via sweat by the amount of time to find your sweat rate.
Water lost via sweat/time spent exercising = sweat rate.
Of course, this will depend on the person and on the weather conditions, and a scale isn't practical for the field, but at the same time knowing your sweat rate under certain conditions will help you determine how much water you need to drink.
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I doubt it's possible to get a sensible answer with realistic equipment, as removing evaporation will make you sweat more. So weighing your clothes while tightly sealed would give an overestimate.
The best way to get a rough idea might be to weigh clothes on a fairly still, humid, overcast day, using those same clothes to dry yourself. A gym session would be a decent substitute. This might be a good time to wear cotton so it absorbs the sweat. Weighing yourself would be interesting (combining sweating with respiration and other losses) but most scales aren't accurate enough - try changing your stance while on them.
When it comes to respiration (and urine production) don't forget that different energy sources use water differently, and the use of these sources changes over the course of prolonged exercise as well as with the starting state of your glycogen stores. Glycogen in particular stores a fair bit of water with it.
This post was sourced from https://outdoors.stackexchange.com/a/19356. It is licensed under CC BY-SA 4.0.
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