I've had a lot of experience exercising in the cold and I can tell you that it's important to warm up your muscles and keep them warm. At 30-40 F quite a few guys in the Army will run in shorts, with their jackets on. I always preferred to run with the pants on and shed the jacket, as that kept my legs warm and allowed me to run faster. In Alaska we ran outside as long as the temps were -25 F or above, so there were quite a few precautions we needed to take up there to keep from injuring ourselves.
Mullet, I'm surprised you had a hickory bow blow up like that on you. I've used mine well below freezing in Alaska and New York. Might be it had a higher than optimal moisture content and didn't like the sudden drop to below freezing. I had two of my older hickory bows fail in compression last spring, after being stored in my unheated garage all winter. I attributed that to the high humidity of upstate NY, since they both did fine in AK, regardless of the weather. We started storing our bows in the house after that, and in humid weather I like warm them up with a heat gun and regrease them often to avoid them taking set. I want to build a big hotbox that fits all our bows on a rack inside. Might make it solar powered, with a backup heater on a thermostat, just to save on my power bill.
Julian