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I’ve been told that when using a down sleeping bag, sleeping in the buff will keep you warmer than sleeping in clothing. Is this true? (I’ve yet to do my own experimenting, as I like to wear long underwear to bed in order to keep my bag cleaner.)
Submitted by – Heidi, Seattle, WA
Your instincts are right, Heidi: As your common sense is telling you, sleeping with clothes on is warmer than sleeping without clothes on. But I think I know where that old myth stems from: It is true that if you wear too much clothing to bed, you can over-compress the insulation so the bag can’t do its thing. You want a little bit of space between you and the bag–this air warms up and creates a nice little microenvironment for you. Get in your bag wearing all your layers, and there’s a chance (depends on how tight the cut of your bag is) that you’ll feel more of a chill.
There’s only one scenario where stripping down might make sense–in an emergency situation where clothes are wet, one person is hypothermic and skin-to-skin contact with a warm body is necessary to jump start the warm up process. But even in normal circumstances, you’ll stay warmer by cuddling up with your baselayers on: Enough heat will make its way through the knit to keep you toasty. Other than that, you’re right, your bag will absorb the oils and sweat from your skin and you’ll have to wash it more frequently. Plus, I think nylon feels just plain gross against the skin. Long johns are the way to go. If you want to sleep naked just to sleep naked, use a removable, washable sleeping bag liner, like REI’s Cocoon Microfiber Mummy Bag Liner.