Why is it that I sweat more when doing the treadmill as opposed to running outside in the heat?

Question

Even though I find running outside harder and more demanding, I drip sweat most of the time while on the treadmill but not outside. The distances are about the same as well as the pace. I may start to drip a little after coming inside after an outdoor run, but not as much as I would during a treadmill run.

Answer 1

when you are outside, you have wind cooling you off. while inside you don't

Answer 2

no wind will do that

Answer 3

***

I do a lot of both, outside running and treadmill running (the treadmill for the periodic repeat work, which on pavement tears my glutes up).

You likely are running harder when running outside - most folks would agree to that.  And you are likely sweating as much, or even more.  However, unless you've got a fan blowing in your face while on the treadmill, even on a still day you are being cooled by more breeze running outside than on the treadmill.  

Cooled - and also dried!

If any lesson is to be learned here, it's get the fan blowing strong (at your feet or midriff) when running inside on the treadmill.

Regards,

Phil

Answer 4

I agree wind likely has something to do with it, however the humidity in your home may affect it as well. That is, the more humid it is inside your home, the less the sweat will be able to evaporate off of your skin into the local atmosphere (the room the treadmill is in). SO, if it can't evaporate from you it will drip off of you.

Conversely, if wherever you are outside is relatively arid, your sweat will evaporate and fly away as a gas long before it has a chance to make you look like you just jumped out of the shower.

Oh, and as a side note (you may already know this), your treadmill run is less demanding because the treadmill surface is much more forgiving than the asphalt/concrete outside...its somewhat flexible surface returns some of the downwards energy to your feet, giving them a tiny boost on the way back up. Less energy lost = less energy needed for each cycle of your stride(s).