Originally Posted by
MinnMan
If you read my other posts in this thread, I'm not at all convinced that a base layer is cooler. But whatever you are going to do, it is counter-productive to wick away drops of sweat rather than allowing them to evaporate against your skin or in a soaked layer that is against your skin.
BTW, even in 80% humidity, evaporation of sweat is your friend. Right next to the sweat droplet, the relative humidity is 100%, so interaction between moist (80% humid) air, sweat, and your skin will result in evaporation and therefore cooling. But in this case, high airflow is important because the amount of water vapor that can be evaporated into each air parcel is limited.
I know you didn't take the opposite position. You came out swinging at me by telling me I've got the physics wrong. However I'll stand by my initial post. And since you are attributing implications to it that I did not say, then you simply are misunderstanding what I said.
Originally Posted by
Iride01
I'd think a base layer will just keep more sweat in which in turns means that you are holding more heat next to your body. For anything over 70ºF I'm only wearing one layer.
Even if the sweat isn't evaporating at a fast rate, just the fact it can drip off of you means it's carrying heat away from you.
In my case sweat accumulates faster than it will ever evaporate. So an ever growing pool of sweat against my body will be overwhelming any cooling from evaporation. Cooling effect from evaporation occurs on the surface. If I have too much sweat between me and the surface, I won't get enough benefit.
Believe me, at no time, other than a short time after starting my ride in the current temperatures here are me or my clothes dry. I simply sweat a lot. There have been times when I stop that there is steady stream of sweat dripping from me. I can't imagine how keeping that sweat on me will benefit my body.
Sweat dripping off of me does carry away heat with it. It has a measurable temperature and whether or not it is the same temperature or cooler does not matter. It is taking away heat that once was belonged to me. So the total heat contained on and in my body is reduced. Don't confuse heat and temperature. I know I do that too often.
Have you ever taken a towel when you come in from the heat and wipe the sweat off of you? Then you should realize that by removing the sweat that is not immediately being used for evaporation, you get a much better cooling effect on your skin.
Why? Because you've made a more ideal situation for your body to benefit from the cooling effect of evaporation. You've removed the excess sweat that buffers the effect and you've brought the surface being cooled in much closer contact to your skin.
You body benefits from bringing the cooling effect closer to it. A base layer and outer layer will only serve to keep it further away.