A resting body doesn't generate much heat through muscle activity. Feet are often the first part of the body which get cold. They are furthest away from the body core, where heat is generated. On it's way down the legs the blood gives off heat to the upper and lower legs before reaching the feet. When it reaches the feet it has already cooled down. In order to preserve heat, the body will reduce warm blood flowing to the outer extremities.
Take your goretex jacket. Close the zippers. Pull the sleeves and hood inside the jacket. Now you have something like a goretex bivy bag for your feet. Pull this over the foot end of your sleeping bag. Firstly, this will add an extra insulation layer to your feet and keep them warmer. Secondly, it protects the foot end of your sleeping bag from getting wet. When the foot end of your sleeping bag brushes against the tent wall, it may wick off condensation moisture, which may have formed on the tents wall. If your sleeping bag gets wet, you'll loose heat faster and your feet will get colder.
Pull the sleeves inside the jacket.
Tuck the hood inside.
Pull the jacket over the food end of the sleeping bag.
What do you think? Do you have any cool tricks and tips?
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