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Is Naked Warmer?

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?


Dear Kristin,
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


Whoever told you that probably just wants to get you naked! I think I know where that old wives tale 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.

There’s only one scenario where stripping down makes sense–in an emergency situation where one person is hypothermic and skin-to-skin contact with a warm body can jump start the warm up process. Otherwise, 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, use a removable, washable sleeping bag liner, like the ones you’ll find at

1 Comment

  1. diesel

    My experience tell me this: sleep naked always if there’s no sign of a possible avalanche.

    I’ve been in many high altitude expeditions in three Continents and have explored many vertical and horizontal caves and underground systems. Sleeping bags are best when they’re good. Don’t try to get a cheap offer and trade it for your safety or comfort.

    In mountaineering, especially when camping at very high altitudes (5,000 metres or higher) it is recommended to sleep naked.

    First, we use only down feathers sleeping bags OR linear single fiber ones -Hollofill is one of the materials made that way. The specs can go from good for 0ºC to -40ºC. Kelty, Big Agnes, Valandre, Marmot… there are many options with high quality standards. Differences are huge in price between a good sleeping bag and a bag for laying down.

    One of the main reasons why sleeping naked is more comfortable and safe is that moisture in our clothes stays there for a much longer period of time than on the skin.

    Second, the air cushion of warm air that our body produces by means of its own heat, is maintained between the skin and the inner layer of down -or fibers- and these let the moisture pass through their loose structures, then it’s evaporated or frozen on the outside shell of the sleeping bag, keeping your body dry.

    One should always make sure to undress when already inside the bag. The boots and all layers of socks must be kept inside the sleeping bag as well. This helps to dry them and keep them warm for the next morning. You can leave your parka and windbreakers outside and use them as pillows.

    Going to the loo in such situation will take its time. But, if weather is just around -10ºC, you can grab your thermic undies and go outside without much fuss. Just make it fast!

    Camping at warm places asks for another layer, if possible: use a light cotton sheet inside the sleeping bag. It will pass the sweat to the outside as vapour and you’ll feel that smooth and fresh sensation when in contact with cotton.

    Never cover a proper sleeping bag with anything. This will shut the shell’s properties of heat exchange and you’ll feel colder or smothered.

    Try sleeping naked at home. Always take a shower before bedtime and you’ll experience why sleeping naked is much better. Keep your pj’s under the covers and use them if you have to get out of bed. You’ll find yourself rested and fresh in the morning.

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