Originally Posted by
woodcraft
Sweating doesn't cause cooling, it's the evaporation- turning from liquid to gas- that does it.
If the sweat runs onto a loose-fitting jersey, & evaporates there, it cools the jersey, but not as much the skin.
By keeping the evaporation right at the skin, the base layer produces more cooling with less sweat.
Good explanation. But the only conclusion I can draw from it is that in hot and muggy conditions the only jersey should be the base layer, no over-jersey. Best contact with the skin and best exposure to the air flow generated by motion of the bike. I guess we would have to carry everything in an under-saddle bag. Except the paunch. What would we do with the paunch?
Or a very tight over-jersey with no base layer.
One thing is for sure, despite the mechanism of cooling of a base layer, adding it as a second shirt for evaporative cooling is also insulating.