What to wear in your sleeping bag

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Harvestman

Bushcrafter through and through
May 11, 2007
8,656
26
55
Pontypool, Wales, Uk
That's often quoted, but I fail to understand how that could be scientifically correct. I view it as insulation + more insulation = most insulation (unless the clothes are so bulky that the sleeping bags loft is reduced). Wearing (dry) clothes inside a tent will make you warmer than being naked inside a tent - it must be the same principle inside a sleeping bag as far as i can see at least.

The idea that is quoted is based on the assumption that clothes add bulk, so that the clothing and the bag are both compressed, meaning they are less insulating. Of course it would also mean that your sleeping bag would feel like a straightjacket, so like you I don't buy it. Insulation is insulation. the bag doesn't keep you warm, it just slows the loss of heat from your body. Wearing clothes in a bag further slows that heat loss.

I wear as much as I need to be warm. Depends on the bag, and the temperature.
 

John Fenna

Lifetime Member & Maker
Oct 7, 2006
23,135
2,873
66
Pembrokeshire
If you wear clothing that is damp from "insensible perspiration" ie the moisture your pores give off all the time but you do not feel, never mind liquid sweat from your days exertion, then you will use body heat to dry the clothing - making you feel colder.
Using dry clothing, or sleeping naked, avoids the need for body heat to dry your kit - so you feel warmer.
Insulation relies on "Dead Air" that is dry, non circulating air to avoid the transmission of heat (vacuum is better - but I do not fancy carrying a thermos that big) - so dry, clean clothing works as insulation. Clothing clogged by moisture, body oils, mud etc is a poor insulator. Wicking clothing or Wool that locks the moisture away from body contact works well. Insulation materials that are used in the making of sleeping bags is ideal - so Primaloft or down trousers or tops are ideal PJs - except that like all PJs the can be too form fitting and ruck up to constrict joints and "body-forks" (knees, elbows, groin, armpits) and become uncomfortable and - in the rucking, compressed and inefficient insulators.
The best thing to wear in a sleeping bag is another sleeping bag!
Silk or cotton Liner bags in summer help prevent sleeping bags getting dirty and inefficient, while in winter inner bags of down, Primaloft type insulation, wool, fleece etc help keep you warm and if then lined with your summer liner are warm and easier to keep clean and efficient.
If they ever invent thin liners that do not ruck up and introduce me to the horrors of bondage I will use them!
As it is I find even the ones that tie into the foot of the outer sleeping bag try their best to hog-tie me (I am a restless sleeper) but thicker bags are more restrained...
As it is I tend to use sleeping bags more as quilts these days (with a good insulating mat) and find comfort/warmth from this combo almost exclusively :) In really cold conditions I have a square footed -10 rated Down sleeping bag that is toasty yet not constrictive, which I can fasten up and sleep well in. In winter I sometimes wear a wool shirt in bed - two reasons... one - I often find that I need my arms outside the bag to get my duff shoulder comfortable and - two it gives me pockets in which I can stow my socks/fresh grundies to ensure they are warm and dry in he morning!
Has anyone tried "Vapor Barrier" PJs ?
 
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Andy BB

Full Member
Apr 19, 2010
3,290
1
Hampshire
I think the argument is - what happens to the water vapour you produce overnight - something like 1-2 litres a night. Adding clothing means that it is much more likely the water vapour will condense inside the clothes/bag, rather than exiting the bag. Either skin, or just a base-layer, produces much less of a condensation risk, and the heat your body produces finds it easier to drive the water vapour through the bag to the outside, leaving you dry and warm rather than damp and cold. My own experience supports that, but I accept some come to other conclusions!
 

bearbait

Full Member
Rab mummy silk liner +/- merino longjohns and T according to temperature. Sometimes down bootees to start with if tootsies are particularly cold initially. If it's warm sometimes just the liner on its own.

The longjohns and T are for bed only: not worn during the day.

As some others have said, I also find it harder to warm up wearing regular clothes in a bag. And more constraining.
 

MikeLA

Full Member
May 17, 2011
2,005
332
Northumberland
I'm of the wear clothes inside camp. My reasoning being that if I'm carrying insulating layers with me, why not use them at night and bring a lighter sleeping bag. They don't serve much purpose inside your rucksack... So usually for me its a softie jacket, with base layer underneath, and just normal trousers, socks. If my clothes are wet, then if possible I will take them off first/change into dry clothes.

Same here for the same reasons
 

tsitenha

Nomad
Dec 18, 2008
384
1
Kanata
In summer a t-shirt and jockey shorts, winter time wool long johns, wool socks if need be. I never keep wet clothes in the bag with me, through sublimation wet clothes will freeze dry in winter under a cover. Socks are washed and again hang dry or freeze and sublimation again takes control. Wet clothes add a lot of moisture in your bag, can your bag let all that water vapor out and itself keep its loft? I also wear a tuque in winter, head net in summer (mosquitoes)
 

mrcharly

Bushcrafter (boy, I've got a lot to say!)
Jan 25, 2011
3,257
44
North Yorkshire, UK
That's often quoted, but I fail to understand how that could be scientifically correct. I view it as insulation + more insulation = most insulation (unless the clothes are so bulky that the sleeping bags loft is reduced). Wearing (dry) clothes inside a tent will make you warmer than being naked inside a tent - it must be the same principle inside a sleeping bag as far as i can see at least.

I thought it was down to the mitten effect. Mittens are warmer than gloves. How come?

Well, wearing gloves actually increased the total surface area.
But in a sleeping bag you are in the bag so it shouldn't make any difference - but it does seem to do so.

So maybe it is down to the dew point ending up in the layer of insulation, so you have damp insulation.
 

santaman2000

M.A.B (Mad About Bushcraft)
Jan 15, 2011
16,909
1,114
67
Florida
That's often quoted, but I fail to understand how that could be scientifically correct. I view it as insulation + more insulation = most insulation (unless the clothes are so bulky that the sleeping bags loft is reduced). Wearing (dry) clothes inside a tent will make you warmer than being naked inside a tent - it must be the same principle inside a sleeping bag as far as i can see at least.

The idea that is quoted is based on the assumption that clothes add bulk, so that the clothing and the bag are both compressed, meaning they are less insulating. Of course it would also mean that your sleeping bag would feel like a straightjacket, so like you I don't buy it. Insulation is insulation. the bag doesn't keep you warm, it just slows the loss of heat from your body. Wearing clothes in a bag further slows that heat loss.

I wear as much as I need to be warm. Depends on the bag, and the temperature.

Same here for the same reasons

Add me to theses three..

I thought it was down to the mitten effect. Mittens are warmer than gloves. How come?

Well, wearing gloves actually increased the total surface area.
But in a sleeping bag you are in the bag so it shouldn't make any difference - but it does seem to do so.

So maybe it is down to the dew point ending up in the layer of insulation, so you have damp insulation.

I see your point but the glove/mitten comparison could also include the two part mitten/glove combos (a wool or polypro inner glove as a liner covered by an outer mitten shell?)

Most of the discussion has revolved around cooler or cold weather as I suspect the OP intended? However in Summer I usually strip as bare as the camping company will allow and just sleep on top of a light bag.
 

waves

Member
Mar 27, 2015
18
0
West Sussex, England
That's often quoted, but I fail to understand how that could be scientifically correct. I view it as insulation + more insulation = most insulation (unless the clothes are so bulky that the sleeping bags loft is reduced). Wearing (dry) clothes inside a tent will make you warmer than being naked inside a tent - it must be the same principle inside a sleeping bag as far as i can see at least.

I've no idea of the science but it was quoted to me as a younger man and I've found naked or boxers works best for me. Being a helpful chap I always used to pass on this advice to any girls that were camping with me too ;-)
 
Jan 12, 2015
7
0
United Kingdom
I am firmly in the camp of wearing fresh clothes into bed, no matter how many there are. If I don't have to worry about what I'm carrying then I usually take a pair of pjs along. I also have a pair of big fluffy slipper type socks which I tuck my bottoms into (I get crazy cold feet even in the summer!) and sometimes I'll sleep with a hoody or jumper on - I prefer hoodies over hats because they keep the warmth in at your neckline. If I have to worry about what I'm carrying then I tend to wear next day's clothes or base layer to bed so I have something dry to wear. New socks to bed are a must!
 

Goatboy

Full Member
Jan 31, 2005
14,956
17
Scotland
Don't overlook the power of a hotwater bottle. Doesn't have to be a trad rubber jobbie, I usually use a wide mouth Nalgene stuffed inside a sock to avoid burns. Also means you have liquid H2O in the morning rather than melting ice in winter. Makes for a very cosy sleep.

Sent via smoke-signal from a woodland in Scotland.
 

Dave

Hill Dweller
Sep 17, 2003
6,019
9
Brigantia
Yeh, I found that a nalgene will dry one swedish woolen surplus sock, in your bag, overnight in the arctic if filled wit boiling water. If you put two over the nalgene, they'll still be a little damp.

I only wear nanok booties, and a 200gsm woolpower balaclava. I have loose wide merino headband, which would work over my nose, if sleeping outside in extreme cold.

But the pillow and the hood on my bag work really well.

When I was sleeping in a bag in a quinze, and its just above freezing, the glands in my neck swelled up, so I could hardly swallow the next morning. [Bt thats why I went, to see what my new limitations were, and I knew there would be unforseen problems. I informed the instructor of that beforehand. So we both expected it and had a plan. A cabin not far from our camp.]

My partner, on the opposite side of the quinze didnt have that problem, so I assume that was just my health. It must have been something to do with the air circulation inside the quinze, which was well ventilated, and is supposed to stay at a constant temp of something like -5˚ however cold the outside temp.

Where-as sleeping outside at -5˚ and colder, I was fine.

Odd, I thought it must be something to do with the air circulation inside the quinze
 
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John Fenna

Lifetime Member & Maker
Oct 7, 2006
23,135
2,873
66
Pembrokeshire
Don't overlook the power of a hotwater bottle. Doesn't have to be a trad rubber jobbie, I usually use a wide mouth Nalgene stuffed inside a sock to avoid burns. Also means you have liquid H2O in the morning rather than melting ice in winter. Makes for a very cosy sleep.

Sent via smoke-signal from a woodland in Scotland.

One of my regular dodges :)
 

davidpingu

Forager
Nov 3, 2012
132
1
Cwmbran
John sort of touched on it already but I always like a layer between my skin and the inside of a down bag particularly because I was told that oils from your skin will seep through to the down over time and reduce its insulating properties.
I like clean fresh clothes for the same reason so I usually wear merino leggings and a cotton t-shirt.
For me a decent sleeping bag is a big investment so I try and keep the inside as clean as possible. Clothes are less of a faff to chuck in the wash usually!
 

Andy BB

Full Member
Apr 19, 2010
3,290
1
Hampshire
John sort of touched on it already but I always like a layer between my skin and the inside of a down bag particularly because I was told that oils from your skin will seep through to the down over time and reduce its insulating properties.
I like clean fresh clothes for the same reason so I usually wear merino leggings and a cotton t-shirt.
For me a decent sleeping bag is a big investment so I try and keep the inside as clean as possible. Clothes are less of a faff to chuck in the wash usually![/QUOTE]

Nah. Put my Wiggys in the washing machine after every use. Wiggys recommend it!
 

Andy BB

Full Member
Apr 19, 2010
3,290
1
Hampshire
Do whatever you do with your existing bags - only more often. The human body puts out over a litre of sweat overnight; some reckon its 2 litres. If your bedclothes aren't soaking in the morning, then all that moisture and body oils have gone into your bag. Even if you have a liner, and that isn't wringing wet in the morning, then all that is either in your bag, or has passed through it, depositing the oils etc in the insulation. Apart from the smell, the insulation will also deteriorate if left unwashed.

Your choice though. Some think that bushcrafters should be smelly, dirty and cold:)
 

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