You can even wrap hot rocks in a cloth and take them into your bed with you - no risks involved.
I prefer a hot waterbottle myself but "back in the day" it was common to heat a brick in the oven, wrap it in a towel and use that as a bed warmer
These days, if it is particularly cold, I will fill my drinks bottle (usually a metal one but I have used an MOD one) with near boiling water, slip it into a spare sock or Tshirt and use that as a hot waterbottle. It is usually still warm in the morning and can be used for a first brew when the rest of the water in camp is still frozen
During my latest "minimal kit" solo I rigged a space blanket as a tarp, went "ground dwelling" on a matress of bracken covered with a thin plastic sheet and had no more covering than my waterproof poncho. The fire was a long pace from my bed and it had a reflector behind it and I was plenty warm... as long as the fire was burning!
The reflector worked well and the foil blanket reflected the fires heat down onto me.
http://www.bushcraftuk.com/forum/showthread.php?t=115088&page=2
I prefer a hot waterbottle myself but "back in the day" it was common to heat a brick in the oven, wrap it in a towel and use that as a bed warmer
These days, if it is particularly cold, I will fill my drinks bottle (usually a metal one but I have used an MOD one) with near boiling water, slip it into a spare sock or Tshirt and use that as a hot waterbottle. It is usually still warm in the morning and can be used for a first brew when the rest of the water in camp is still frozen
During my latest "minimal kit" solo I rigged a space blanket as a tarp, went "ground dwelling" on a matress of bracken covered with a thin plastic sheet and had no more covering than my waterproof poncho. The fire was a long pace from my bed and it had a reflector behind it and I was plenty warm... as long as the fire was burning!
The reflector worked well and the foil blanket reflected the fires heat down onto me.
http://www.bushcraftuk.com/forum/showthread.php?t=115088&page=2