Breathing in sleeping bag?

Obviously it would be worse in a down bag. I haven't used a mummy bag in a long time and I never tried it. I did sleep with my head on my down jacket one night (in 18 degree weather) and the next morning it was moist enough to seriously compromise the insulation. I can't say that was all my breath but I'd kept the jacket dry during the day. The only other way it could have got damp would have been from humidity in the air.

I've done that before in synthetic bag and when it's cold, everything gets wet, and thus less warm.

Better to have proper head wear – like a balaclava – fleece is okay but not that warm for the weight – synthetic or down hat would be better if it's really cold – has to cover up your neck too

If it's cold enough to bother me in the winter, I bring an acrylic knit balaclava or fleece neck gaiter to wear covering my face.

there's a hole just big enough for my lips and nose to breath outside of the hood of my sleeping bag. if it's truly brutal i can wear a face mask that covers my mouth and nose but has holes to breath through. i cannot think of a good reason to ever breath into my sleeping bag. the volume of water vapor exhaled in a night would degrade the loft of my down sleeping bag and that would be bad.

I cinch the collar down tight but make sure my nose and mouth are sticking out. If it's cold, I wear a balaclava. If it's really cold, I pull the balaclava over my nose and mouth. There's a lot of condensation in the balaclava in the morning, but it's polypro fleece so nearly all of the moisture shakes out. It takes a lot longer to dry out the sleeping bag.

I'm still working on my 12 year old grandson not to breathe into his down bag at night!

> I cannot think of a good reason to ever breath into my sleeping bag. The volume of water
> vapor exhaled in a night would degrade the loft of my down sleeping bag

Exactly. Head gear is needed.

Cheers

>Head gear is needed.

Unless you exhaust your breath outside the bag. For instance, a swim snorkel in your mouth – which would take a little training to use, but people with sleep apnea learn to use a CPAP machine all through the night. Ideally, there'd be two check valves so you breathed out one tube and in through another.

If you take that step, you've got the possibility of saving even more heat. Because typically we breath in ambient, cold, dry air and exhale warm, moist air. The breathing passages in your nose help to retain heat and moisture but an external heat exchanger could do even more.

Aside: absolutely try to train yourself to nose breath instead of mouth breath – you'll retain more heat and moisture (and moisture in air IS heat).

There are heat exchangers and difusers sold for skiiers and mountaineers. They each want them for the larger surface area in the event of being buried in an avalanche. Additional, the HX function retains more heat and moisture – a big issue at 25,000 feet where you're always dehaydrated and liquid water is hard to carry or melt.

For BPing, the added surface area doesn't help, but the HX and moisture retention would. Simplest would be exactly a swimmers snorkel with some sorbant packed in it to capture heat and moisture from the exhaled breath and transfer it to the inhaled breath.

Well I guess that one's settled pretty unanimously lol. Thanks for the feedback. And good thinking on the HX, but I think I'll keep it simple and just go with the balaclava. I think keeping my head out of the bag will be the hardest thing to change honestly.

You don't have to keep your whole head out, just your face!

my bag has some netting in the footbox and is a little long for me. when i go tarping, sometimes i forget my bug net. so if there are lots of things flying around, i go into my bag head first, tighten the drawstring under my feet, and breathe close to the netting. honestly i think they should make all bags like this. ^_^

In the 1970's, when temperatures got below -10F, we just cinched the bag until only a small opening remained, then stuck a wool sock or mitten into the hole on the inside and breathed through it. The thick fabric warmed the air as it came through, the wool never seemed to get very wet, and it dried quickly after wearing it a while.

I haven't tried this with fleece, it probably should work.

I have never owned a down sleeping bag and I always do this. I sleep with my sleeping bag backwards and the hood directly over my face. I haven't had problems and I generally feel warmer. I have done in 15-25 degree weather as well, sometimes I end up with a small cold spot but it didn't bother me, but those times were all with keeping a large fire going all night… so that might make a difference. Keep in mind I am talking about a synthetic bag.

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put your mouth near the where fresh air enters the bag. I usually cinch down to a small hole left in the hood or top bag and I've never had a problem. Just expel outside the bag and you should be just fine. Give it a shot.

The few times I've winter camped so far, I just leave a hole over my face and parts of the edge of that hole have been wet/frozen in the morning. I use a down bag.

Out this Feb and temp dropped from 32F to 0F. fortunately we were expecting mid-teens so we were prepared. Found tossing my fleece over the head of my bag kept the moisture to a very low level and allowed a bigger breathing space so I didn't feel confined. Done it without the fleece many times and the bag edge usually gets damp. But it drys fast at that temp too. R.H. is about 10%.