Originally Posted by
Seattle Forrest
Paradoxically, this might be your problem.
I used to wear just a tee shirt under a goretex parka (uninsulated) on long mountain hikes and on bike rides. I'd sweat a lot, and there wasn't much less to remove, which is a bummer. Turns out I'd sweat less if I wore more; a mid-layer for warmth actually kept me from sweating.
The best story I've come up with to explain it is if I'm going out in a t-shirt and thin jacket when it's 40 F, I'm cold, and my body is trying hard to produce more heat, above and beyond what comes from the exercise. That doesn't make a whole lot of sense, but it's reliable even if I don't understand it.
What was probably happening was that the mid-layer was wicking sweat away you. So you had relatively dry air near your skin, letting sweat evaporate to cool you. Some of the "missing" sweat would have been buffered in the mid-layer.