I’m what you call a recreational runner (~3 times a week, more often if chased). Nowadays you see lots clothes with high tech fabrics that promise to “wick” away your sweat, i.e move it from the surface of your skin to your next layer of clothing or into the air. I own some of these shirts, and they work great! But what’s the actual benefit?
In the summer, the ads proclaim wicking sweat will keep you cooler, and in winter will keep you warmer. I wholeheartedly buy the ‘warmer in winter bit’, since nothing is colder than getting hit with the winter wind in a wet shirt. But I’m skeptical the same mechanism can also keep you cooler in summer. That’s like saying tax cuts for the rich are good for booming economies as well as recessions. :dubious: (sorry, couldn’t help it).
To make a long question longer, and maybe more scientific, by what mechanism does sweat cool you? Is it primarily by allowing greater conduction of heat from the skin to the air, or is it conduction of heat from within the body out onto the surface of the skin?
If the sweat is not wicked, there are two options, keep the sweat in or absorb it. Although wicking and absorbing are very similar, the hope is that the capillary action of the wicking will simply transport the mosture to the outside of the fabric rather than keeping it inside (cotton).
My experience with wicking fabrics is hiking, usually socks and undershirts in the winter to keep wet fabric off my body. I also have a sleeping bag that is incredible, I have woken up in an inch of water and not known it due to the sleeping bag wicking everything away. As far as running goes, I would assume it would be for similar reasons in both seasons, just to get the moisture away from your body but not hold onto it.
Since you get the winter part, I can answer the summer part and your final question in together. When the body puts water on our skin, it takes heat away from our body in order to evaporate the water (sweat), making us cooler, your first guess.
IANATextile expert, btw. Someone else may be along shortly.
And can’t we keep the political crap in GD or the Pit? 