They say the way to stay warm in your sleeping bag is to strip down to your birthday suit. In the many survival manuals I've consulted, they all seem to be agreed on that point. But I say it ain't so.
In my experience, a thin layer of cloth next to the body makes a huge difference in staying warm. This seems apparent to me, in my own bed at night. A blanket or comforter by itself is not nearly so warm as a comforter lying on top of a cotton sheet.
I've also found this to be true in the field, as I find a pair of socks, under-drawers and a t-shirt (or even long underwear) keeps me far warmer inside a sleeping bag, than just curling up nude. I've determined to try wrapping up in a standard, cotton bed sheet inside my sleeping bag, but I haven't done much cold-weather camping in recent years.
Some years back, I took the Boulder Outdoor Survival two-week course. It gets a bit chilly, sleeping out in the desert in May. But one of our intrepid number (who allegedly lived in a cave in California) chose to wrap up only in a cotton bed sheet, while the rest of us used wool blankets. I wouldn't want to try that without a blanket handy for back-up, but it seemed OK for him. He also wore a loin cloth, but the most disconcerting thing about him was the Mountain Man beard with the California surfer accent. But I digress.
This all springs to mind recently, because I had to spend much of my weekend shoveling snow (a whole lot of it.) The temperatures were in the twenties, and I thought I would need my totally awesome Army surplus half/wool, half/cotton thermal shirt. But since I was wearing a "heavy-weight" t-shirt under my usual work shirt, I only needed to add a jacket.
What think you?
Before anyone else springs on this - yes, we know that cotton loses its insulating properties when wet. Therefore, some other thin material might be preferable.
