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Thread: Sleeping Warm in the Cold

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    Member Marc Taylor's Avatar
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    Default Sleeping Warm in the Cold

    Saw the other thread and thought I'd add some notes.

    Keep in mind that there are varying degrees of comfort desired from a cold weather sleeping experience. Some trappers or mushers just want to grab a few hours of rest and then get back on the trail, and others may attempt to stay warm for most of the dark hours, which, in Alaska winter can exceed what's expected of a good niight's sleep in a sleeping bag.

    That being said, it's my belief that as long as we keep the metabolism stoked, one should be able to maintain a high level of comfort from a cold-weather sleeping experience as long as a few basic guidelines are followed.

    I always attempt to over-bag myself but without totally over-burdening myself. Take enough bag!

    The bag must fit and allow for the sleeper to roll INSIDE the bag. No insulation should be compressed by the elbows or shoulders during sleep. Compressed insulation allows heat to escape more rapidly. I always hear that Wiggy bags are heavy. That is because they FIT. We cut them generous because most grown men are WIDE. I WILL NOT sell any man a regular width bag because of this unless he is VERY narrow in the shoulders.

    Use a pad (or two) that REFLECTS heat and does not dissipate it. I would NEVER use an inflatable pad in the winter, for instance. Your body heats the air in the pad and the ground cools it, then you heat it, then it cools it... It will be a constant battle that you cannot win. I will usually take 2 pads or at least some kind of ground cloth under my pad.

    Cot camping: Always DOUBLE your pad requirement. The air beneath a cot is the temperature of the air outside. The ground is a constant 31 or so. Therefore, sleeping on a cot in -20 temperature will mean that the -20 air will constantly be below you as well as above, robbing you of precious heat.

    Therefore, choose the ground over a cot in the winter unless you've got enough pad to make up for the heat loss.

    Sleep with minimal clothing on. For the same reason that we cannot just put on a bunch of layers and flop down on the snow and get a good night's sleep, too much clothing worn in a bag will stifle the body's heat from filling up the expanse (loft) of the bag. That expanse will fill with either cold or warm air; your choice! The warm air needs to meet the cold air at the outside of the bag, not anywhere inside the bag. DISTANCE FROM THE COLD is what keeps us warm. Not any amount of clothing worn within a bag.

    Cotton clothing is not desirable as sleep clothing as it attempts to trap the natural perspiration that we lose during sleep. That moisture will demand to be cooled, and therefore it is better to be allowed to pass through the loft and meet the cold air at the shell of the bag.

    I sleep in light fleece. Silk, nylon, polyester -- all good. Just not too much of it. Naked is great, but I don't like moving my legs to the cool part of the bag. Yikes. Just a personal preference not to sleep naked. Many guys and gals prefer it and it makes sense as long as the bag drapes properly.

    Waterproofing a bag will trap moisture. Not desirable. A waterproof shell will create a damp warm environment. We are seeking a dry warm environment.

    Sleep within an enclosure. Tent, tarp, snow cave, etc. It will always be a great deal warmer within an enclosure, even a slight enclosure as long as the wind is not blowing through it.

    Want to warm water and heat your bag? Fine. I've never done that but it makes perfect sense, however, later in the night you will be warming the water instead of it warming you. As soon as the water reaches the ambient temperature of the bag it will be detrimental because the ambient temp inside the bag will be less than 98 degrees (body temp). Ambient temperature inside your bag needs to be above 80 degrees to sleep comfortably.

    Always eat before going to the bag. I usually keep cashews next to my bag and much a handful before zipping up. If you spend enough time in the bag, you WILL get chilled because you are running out of fuel, and you will need to restoke the metabolic burner! No way around that. Cashews are easy to eat and are high in calories. Slow-burning calories!

    Urinate when you must. Don't waste heat on a full bladder. I wind up emptying a jar most mornings, but I don't walk around in the middle of the night and get a chill to pee.

    I always sleep with insulated "booties" on my feet and I NEVER get chilled feet in a sleeping bag. Some prefer socks, but having had my pack boots or mukluks on all day and sweaty feet, the booties allow them to dry and be unconstricted.

    Always wear a balaclava (preferred) or a stocking cap, beanie, etc. I like mine to cover my eyes and come up to just below my mouth.

    I usually take an article of clothing inside the bag and utilize it to stop drafts or take care of cold spots. A cold spot may be caused by an elbow or shoulder compressing insulation during the night. This will happen unless you have an extremely roomy bag.

    However, a bag can be TOO roomy... Keep that in mind. But better to be roomy than tight.

    Hydrated muscles will promote heat retention within the body.

    Don't sit around until you are cold then turn-in to sleep. Always "jump start" the warming process by doing chores around camp or even exercising to warm up the body before taking it to the bag. Cold feet take a while to heat up inside a bag, for instance. Walk around a bit before turning in.

    Make sure your draft tube is on the INSIDE of the bag! You have NO idea how many customers I get in here who don't know that! Take the time when turning in to run your hand the length of the zipper to make sure the draft tube is properly covering the zipper. It will leak a ton of warmth if not properly covered.

    Sleeping warm in the cold is not rocket science, but it is not an exact science either. There are some bodies who just cannot sleep comfortably anywhere other than a heated home. There are varying degrees of cardiovascular fitness and those with circulation problems just will not sleep as warm as someone who is fit.

    Women and children generally sleep cooler than men as they do not have the muscle mass that men have. Muscles generate and hold heat. Therefore, a woman will generally need a warmer sleeping bag or more ground padding than a man. Fat requires that it be heated and will to some degree insulate, but it is metabolically inferior to muscle mass. Blood flows to a fat cell and comes back chilled. Blood flows to a muscle cell and comes back at body temperature or warmer if there is activity involved. I'm no Doctor, but just reach into your shorts and feel your butt and see if it is not cooler than your thigh and you'll see the difference!

    This should get a good dialogue started on the subject!

    Enjoy!

    Taylor

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    Marc, excellent summary, thanks!

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    Member hodgeman's Avatar
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    Thank you Marc! Very good info.

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    Member Vince's Avatar
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    Great info.. Marc... and oyur right sleeping cold is not that hard to do... and can be practiced at home by any man...


    i am working on my third wife and am a master of sleeping cold..........
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    Member broncoformudv's Avatar
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    Great write up on sleeping out Marc! Love the butt comment.

    One thing I noticed is the ground is not 31 degrees it is closer to 17 during the winter if I remember correctly which is still way warmer than the ambient air temp most of the time. One more reason to dig down to the ground instead of sleeping on top of the snow.

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    ....great article, Marc...

    -funny, too-

    -I wanted to add something about spruce boughs...-they can make a very effective barrier against the cold ground, under your tent, etc-
    -the more time taken to trim and arrange them, removing as much "pokey" material, the more comfortable-
    (lay the boughs under a tarp first)



    -this subject brings back memories....living in the 8x10 wall tent for seven months on the Westfork(near Chena) while we were building our cabin.-the boys were 2 and 4, with another on the way...Jed was born out there(actually, in our neighbors' kitchen, down the trail)-

    -was nice and toasty with the Yukon stove....but, it had to be fed every 40 min, or so....we basically all ended up sleeping nights wrapped in many wool blanket layers against the cold until morning-
    -the biggest problem was the ice build-up inside the tent-

    ....I think, though....sleeping outside in -20 below zero up there in the interior is a piece of cake , compared to 20 or 30 above, here on the Kenai-



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    I will put this in there, DON'T put a mummy bag on the snow by itself, or you will wake up in a cacoon you can't get of at -40 ( did that, never did it again)

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    Member Marc Taylor's Avatar
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    Thumbs up

    Bronco - My reference to ground temperature was beneath you with your body on a pad. Your body heat will warm the surface under your pad regardless of how good a pad you've got.

    Yes, agreed, the ground gets colder than 32-31, but once you're laying on it, the ground warms up to right at freezing.

    Sheephuntress - Agree with the spruce bough technique, but I rarely do that if I've got two pads because air fills the expanse, however slight, between the boughs. Just my preference. The technique you describe is widely utilized.

    Thanks all,

    Taylor

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    Forum Admin Brian M's Avatar
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    Quote Originally Posted by Marc Taylor View Post
    The air beneath a cot is the temperature of the air outside. The ground is a constant 31 or so. Therefore, sleeping on a cot in -20 temperature will mean that the -20 air will constantly be below you as well as above, robbing you of precious heat.

    Therefore, choose the ground over a cot in the winter unless you've got enough pad to make up for the heat loss.
    I don't have any experience sleeping in a cot, but your reasoning here isn't quite correct. While -20 air is technically colder than 31 degree ground, 31 degree ground will drain heat from your body faster than the -20 air. It's the same reason why a person can survive naked in -20 air longer than if they were immersed in 31 degree water. Water has a much higher specific heat than air, thus it removes more heat from your body than air. The same is true of ground. Due to its higher specific heat, it can be a far warmer temperature than the surrounding air yet pull more heat from your body than the colder air mass. The ground will also pull heat from an air pad at a higher rate than more air under a cot. If I were going to double up on a sleeping pad, it would be on the ground, not the cot.

    Physics works. Sleeping with air under you will be warmer than sleeping on the ground, regardless of the temperature of either.

    The rest of the post was excellent and I certainly jotted down more than a few mental notes.
    Last edited by Brian M; 11-30-2009 at 16:17.

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    I'm still thinking that clothes add an additional layer of insulation, and thus keep you warmer. I camp sleep pretty much fully dressed, but have little experience camping in the cold, so what do I know.

    Anyone have experience with insulated air mats like Big Agnes Insulated Air Core Mat or an Exped DownMat? The Exped DownMat 9 claims R-8, and the Big Agnes Dual Core claims R-6. You would need 3" to 4" of self inflating pad to achieve those numbers, but do they squish down and leave you with a cold shoulder, etc.?

    I'm want the cold hard facts --- but personal experience will do.

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    Member Rock_skipper's Avatar
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    Cold hard facts are, carry a hide around with you.

    I don't know about air mattress's, myself I would'nt even bother taking one out when it was cold.

    Maybe someone on here has had a better exp.

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    I've used an air mattress in early summer once and it froze me to death at 35F. I can't imagine at -35F...
    I've also used the aircore type pads that are a mixture of air and insulation- better but still cool. Thermarests are the warmest pads I've used.

    I like Thermarests OK but if I'm going in really cold weather and weight and space aren't a premium (like with a big sled or vehicle)- I use a conventional foam mattress about 4" thick- bulky but darn toasty!

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    Member broncoformudv's Avatar
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    Quote Originally Posted by Jim Strutz View Post
    Anyone have experience with insulated air mats like Big Agnes Insulated Air Core Mat or an Exped DownMat? The Exped DownMat 9 claims R-8, and the Big Agnes Dual Core claims R-6. You would need 3" to 4" of self inflating pad to achieve those numbers, but do they squish down and leave you with a cold shoulder, etc.?

    I'm want the cold hard facts --- but personal experience will do.
    I have been using the Big Agnes insulated aircore for the past couple of years now and have no regrets it is a great mat regardless of the season. I have used it in the summer, fall, and winter so far both on the ground and on a cot. It does lose a bit of air pressure over night due to the temp changes but I just top it off every evening before hitting the sack. The one thing I really like about this mat over thermarest or closed foam pads is its compact size and lightweight.

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    I've used the non insulated air pads plenty of times, and they're cold even in the summer. Basically they're just R-1. I also have a 3.5" thick REI Camp Bed self inflating pad that claims to be R-7, and it is quite warm. But if an Exped or B.A. Dual Core, really are about the same warmth, I would rather pack that. I also find the air pads to be more comfortable. Of course, if they leak...

    I think I prefer the Exped over the Big Agnes pads, since they have a built in pump. Anyone have any negative experience?

  15. #15

    Default Air mattresses

    My Hunting Pard likes to use an air mattress while I'm fond of my Wiggies ground pad. I have found that my pardner's air mattress actually keeps me warm. I'll explain....

    Best thing about your pardner using an Air Matress (warm or cold season) is when your he humps that "Rubber Bitsh" up the mountain, blows it up til he's red in the face and it's nice an fluffy and settles in for the night. About 2:00 AM you hear that PSSSSSS noise coming from the direction of where he was once sleeping rather comfortably. I laughed so hard that I nearly hurt myself but the exsertion for the chortle warmed me up so that I was nice an toasty the rest of the night.

    I find that his "Rubber Bitsh" is still a running joke in my camp and continues to warm me for the effort each night before I turn in. Best sleeping bag warmer i can think of.
    Yea though I walk through the valley of the shadow of death, I will fear no evil, for the shadow is mine and so is the valley. Thy Glock and thy M14 comfort me in days of civil unrest and terror

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    Default Just say no to cots

    The coldest I have ever been was on a cot. Way warmer to be on the ground with a pad then on a cot with a pad. I dont care if physics says its warmer. Sleeping on a cot is COLD! Mark is correct there.

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    Member AKFishOn's Avatar
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    I have an insulated Big Agnes air mattress, paid a lot for it and worth the money. It is the only air mattress I've used that is light, warm, and gives me the best comfort and I'm a gear junkie (read tried lots of combinations and brands of pads). That said in the winter, for example few weeks back camped out at -3 (I know not real cold but cold none the less) I started my pad layers by placing a pad (older army green pad), a wool blanket, then the Big Agnes air mattress and then another wool blanket on top of the air mattress. I've done the same at -27 and it has worked well. A real thick foam pad would be great but too bulky in my opinion. I have slept on a cot also without the pad, **** cold in my opinion but if layered/insulated right it will work. Once on a cot boots froze to the ground hard as it went from about 25 with a little slush to 0 that night nothing better than getting up to find boots froze to the ground in a tent without a floor.

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    Member Vince's Avatar
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    BUT ???? what if i lit the barrle stove and stoked it with 12 hours of wood and deside to sleep on my bag

    i love insulated tents, with cots and stoves....
    "If you are on a continuous search to be offended, you will always find what you are looking for; even when it isn't there."

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    Member mainer_in_ak's Avatar
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    Mark Taylor,

    Thanks for your post......all good stuff. I laughed a little when you mentioned that women "sleep colder" Some have really cold hearts.....so that is prob. why. But one thing you forgot to post......is "doubling up a sleeping bag". There is a gal that wants to go ice fishing this weekend with me....but she is scared of getting cold. Maybe you forgot to mention in your "tips" how connecting together two sleeping bags could ensure that this gal doesnt get cold?

    You are also right about fat insulating......I can relate with you about that because a stripper with a marvelously plump back-side sat on my lap last weekend.......and her backside was notably colder than the other strippers that passed by. Her behind was so cold.....that I decided to pull out my secret weapon to get her to go away......I told her that I didn't have any money

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    Quote Originally Posted by mainer_in_ak View Post
    But one thing you forgot to post......is "doubling up a sleeping bag". There is a gal that wants to go ice fishing this weekend with me....but she is scared of getting cold. Maybe you forgot to mention in your "tips" how connecting together two sleeping bags could ensure that this gal doesnt get cold?
    My wife and I do this trick regularly. However, if it is going to be getting really cold we don't. Simply because like doubling the diameter of a pipe when you double the diameter of a sleeping bag it seems to be 4X the volume to heat up and much harder to keep the whole bag warm. Of course having the warm body next to you helps heat one side. Also we stuff some of our clothing and whatnot inside that bag to help, but like I said if its gets too cold we found it works best to just be in your own bag. But the added space and ability to sprawl a letting with the added volume of the bags zipped together sure is nice.
    Last edited by Alaska_Lanche; 12-02-2009 at 07:53.

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