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robertsi
03-23-2005, 09:57
Someone once told me that sleeping bags are designed in such a way that you should not wear alot of clothing when you are inside them. Can anyone confirm or deny this? My last cold weather hike about a month ago i started to get a little cold in the middle of the night. Granted it was colder than any other winter hike i had taken before, and i wore most of my clothing to avoid the super chill when i had to get dressed in the moring. Could the fact that i had most of my clothing on contributed to my getting cold?

Just wondering if maybe my sleeping bag is losing its insulation, or maybe im losing my marbles. lol

Thanks
Rob (no trail name yet)

TJ aka Teej
03-23-2005, 10:13
Hi Rob,
I believe the only clothing (worn or not) that will really affect your body temp on a cold night in a zipped up sleeping bag is a hat. Other folks may have other opinons.

Tramper Al
03-23-2005, 10:39
It is certainly a bit of trail lore (or is it myth) that wearing clothes in a sleeping bag makes you colder.

However, the more insulation you have to prevent heat loss between you and the inside of the bag, the less heat will be lost going through the bag, obviously. The only exception (and probably the source of the myth) is that overly tight clothing will not encourage good circulation and you may feel colder.

And of course core body temperature doesn't really change in the range of sleeping warm, sleeping cold or a bit of shivering.

And I agree that hat / balaclava can go a long way toward raising a bag's real world temp rating.

bulldog49
03-23-2005, 10:39
Someone once told me that sleeping bags are designed in such a way that you should not wear alot of clothing when you are inside them. Can anyone confirm or deny this? My last cold weather hike about a month ago i started to get a little cold in the middle of the night. Granted it was colder than any other winter hike i had taken before, and i wore most of my clothing to avoid the super chill when i had to get dressed in the moring. Could the fact that i had most of my clothing on contributed to my getting cold?

Just wondering if maybe my sleeping bag is losing its insulation, or maybe im losing my marbles. lol

Thanks
Rob (no trail name yet)

What I've always heard is that if you wear too much clothing that you compress the insulation in the bag, thus reducing its effectiveness. I wear extra clothing when I'm stretching my bags temp rating but careful to maintain enough room to keep maximum loft in the bag.

Kozmic Zian
03-23-2005, 10:47
Yea......They make liners for sleeping bags to increase their warmth ratio. Most liners are like fleece or thin down, usually that would be warmer than your clothes. Most of these liners only provide about 10defahrenheit to your warmth. So it stands to reason, that wearing your hiking clothes or jacket to bed couldn't help much, but I've been out there when it's really cold, and I find myself putting on my jacket and glove liners to sleep. Call it psychological. IMHO, I really believe that the bag itself, provides the max warmth, and you would do better to sleep in dry shorts and dry shirt. KZ@

Jaybird
03-23-2005, 10:48
Yo robertsi:


first, look @ your calendar...its MARCH 23rd...it's SPRING!


but, to answer your question...if you get cold in your bag...you can wear a layer of clothes...maybe your bag is not suited for 3 (or 4) season hiking?

if you're an earlybird hiker (starting before April) you'll need @ least a 20 degree or below bag.

If you need more info. about your particular bag's effectiveness in maintaining warmth..contact the manufacturer or your local outfitter store.

If i get cold... i just put on an "extra layer" of clothes.

Good luck with yer hike...

see u out there: Apr 28-May 20 Hot Springs, NC to Pearisburg,VA

Panzer1
03-23-2005, 11:53
I have done a lot of winter backpacking and what I would do is to take off only my boots and get into the bag with hat, gloves, jacket and pants. But only if it was cold enough to warrant this. Otherwise if it was not really that cold, I would take off as much as I could in order to get comfy.

Panzer

Mags
03-23-2005, 13:18
Winter backpacking can be great. The weather is crisp, the scenery beautiful, and an overall sublime experience.

However, you need to keep a few things in mind that can be different than 3 season hiking. Staying warm is one of them at night is one of them.

How to stay warm at night? Here are a few tips that may help:


** Mangia! Your body is a furnace and to keep it going you need fuel (calories) to keep it going through the night. Have something laden with fat and carbs. Lots of it. You may also want to have some cookies/candy handy for eating in the night. Some quick sugar to burn in the night can often mean the diifference between a cold night and pleasant slumber.

** Hydate! A de-hydated body will not process calories as efficiently..causing you to be cold. In the winter, it is very easy to get hydrated due to the cold, dry air; since you are not feeling hot you tend to drink less further excaberating this cycle. Something like warm Kool-aid or jello is great for drinking at night: quick sugar (calories!), water and hot.

** All this hydration may mean you may have to go to the bathroom at some point. DON'T HOLD IT IN! Your body will be using up precious calories to keep the liquid warm. Guys, use a (well marked!) pee bottle. An old gatorade bottle works well. Gals, they make a few different items. The lady-j is an item some of my female friends use.

** Clothing: As others have mentioned you do not want to wear so many clothese that you are compessing the loft of your bag or have no space between you and the sleepinb bag. A sleeping bag works by warming up the air between you and the body. No space to warm up? Cold night! I suggest just wearing long underwear only (along with dry socks and a balaclava.)

For winter backpacking I strongly suggest packing a pair of long underwear that is not worn during the day. During the day, your long underwear will get damp. When you crawl into bed, guess where that moisture goes? Yep..into your bag as your body hear dries out the long underwear! A pair you only wear for bed will help be dry and warm. Ditto with dry socks. Finally, why a balaclava vs a hat? A balaclava wiill cover your neck and a bit of your face, as well as your head. Keeping in more heat. A very essential thing for winter backpacking! If you get warm, you can always roll up the balaclava. Always, always, wear a hat at night for winter backpacking.

**Sleeping pads: The cold ground will rob precious heat out of you. Having sufficient thickness between you and the cold ground is VERY IMPORTANT. I suggest two pads during winter. I've had good luck using my 3/4 length Z-rest with a blue foam pad.

**Exercise: Believe it or not, doing some light but vigorous exercise before going to bed can help immensley. Do some jumping jacks, situps, etc. Something to jump start the metabolism. Not so much that you are sweaty, but enough where you can feel yourself heating up. You will warm the bag up very quicky.

**Hot water bottle: Some hot (not boiling!) water in a Nalgene (and, if you are careful, a Gatorade bottle) wll do wonders. Plus, you will have something to drink during the course of the night.

Youngblood
03-23-2005, 15:27
Someone once told me that sleeping bags are designed in such a way that you should not wear alot of clothing when you are inside them. Can anyone confirm or deny this? My last cold weather hike about a month ago i started to get a little cold in the middle of the night. Granted it was colder than any other winter hike i had taken before, and i wore most of my clothing to avoid the super chill when i had to get dressed in the moring. Could the fact that i had most of my clothing on contributed to my getting cold?

Just wondering if maybe my sleeping bag is losing its insulation, or maybe im losing my marbles. lol

Thanks
Rob (no trail name yet)As to wearing clothes in your sleeping bag, the physics are that dry lofted insulation keeps you warm... the more you have the warmer you will be. The key words in all this is 'dry' and 'lofted'; if it's wet or compressed all bets are off.

Youngblood

lumpy
03-23-2005, 16:12
Would an overbag work as well as a bag liner?

The Old Fhart
03-23-2005, 17:28
Would an overbag work as well as a bag liner?Actually, it might work better. If you have a snug fitting sleeping bag then wearing much extra clothing could compress the bag's insulation. If the sleeping bag has better insulation than the clothing you add, compressing the bag's insulation will make you colder.

If the sleeping bag is loose fitting so you can add clothes or a liner without compressing the bag's insulation, you will get the benefit from the extra insulation. This is just like in a house where you talk of "R value" of insulation, R-23(thicker) is warmer than R-19, is warmer than R-13, etc..

If your sleeping bag is snug and you can't add clothes or a liner without compressing the bag's insulation, adding an overbag gives you the added insulation which equates to warmer.

Buying a bag that is too snug may save weight but you will not see any benefits if the insulation compresses and turns your 20 degree rated bag into a 35 degree bag.

WalkinHome
03-23-2005, 23:03
Took a quickie course from the SERE (Survival, Escape, Resistance and Evasion) cadre from Brunswick Naval Air Station (the downed pilots school) and their guidance was that the human body will transmit heat out to the first layer/barrier. Normally, your body heat would heat all the space inside your bag making for a comfortable night. For the most part this has worked for me (except for my feet) but I have been known to add long underwear and a tee shirt in the bag. If your bag has too much room in it your body might have a harder time of it.

Jester2000
03-23-2005, 23:07
Took a course called BEER (Billville Evasion, Escape, Regret nothing in the morning) and it says that if you have too much room in your bag you should put a girl in there.

peter_pan
03-24-2005, 08:10
Agree with Mags and Youngblood's comments......

Will add that wearing dry fleece long johns is more effective than a bag liner in that it hold a micro clime of warmth next to the body without restriction and readily allows body heat to the dead air space between you and the bag/quilt....it is a more multi purpose item in the pack also...It will also eliminate the rude awakening of cold nylon if you shift to a preveously unheated portion of a non-close fitting bag...

Most cold spots at night occur when an elbow, shoulder, hip , knee, foot shift and press outward thus reducing loft at that spot....The reduced loft as the bag quilt tapers into the compressed area below you but not yet insulated by a firm pad is another spot of cold threat....

One more point on the wearing additional items.....DOWN BOOTIES.....I've been using my current pair since 1982.....they are the pentultimate in thermocline retention for the feet....they add significant loft over toes... and they soften and blunt the toe against the bag tension point issue....Gram for gram these are the most warm and luxurious items in my pack...They also serve as camp mock in dry weather, as they have a closed cell foam sole inside of a 500 denier outer sole shell....4 oz /pr...

While wet items sereously degrade a bag...dry does not.

If the bag makers can make you believe that to be effective you must use them without clothes.....they will sell a lot of extra bags for colder seasons.... will add in thier defense that there are a lot of variables to any particular bag/quilts warmth....and reducing the "standard for comparision" to an unclothed body reduces the comparision issue/problem.

dougmeredith
03-24-2005, 10:11
Good post. A couple of issues.


All this hydration may mean you may have to go to the bathroom at some point. DON'T HOLD IT IN! Your body will be using up precious calories to keep the liquid warm.
The heat that you lose is proportional to the surface area of your body. Retaining urine doesn't increase the surface area and won't increase your heat loss.


A sleeping bag works by warming up the air between you and the body. No space to warm up? Cold night!
I'm not so sure about that. A bag works by providing insulation that slows the loss of heat from your body. The air is warmed by your body transfering heat to the air. The more air you have to warm, the colder you will be.

Doug

Mags
03-24-2005, 16:29
[QUOTE=dougmeredith]

The heat that you lose is proportional to the surface area of your body. Retaining urine doesn't increase the surface area and won't increase your heat loss.

****

Not quite - anything your body has to do requires calories. Calaories keep you warm. The more calories you burn over the course of the night, the less likely you likey you are to have enough calories to sustain you. If your fuel tank is running low you WILL get cold.



*** I'm not so sure about that. A bag works by providing insulation that slows the loss of heat from your body. The air is warmed by your body transfering heat to the air. The more air you have to warm, the colder you will be.

To a certain extent..but if you bundle up to the point that you have no dead space in your sleeping bag, you will not be warm. Obviously if the bag is TOO big, you are quite correct. But,ever wonder why in military cold weather training the powers-that-be- make the soldiers sleep in the nude?

I perhaps should have my explanations more clear, but I still stand by them.

WalkinHome
03-24-2005, 17:37
Jester lies - he is the founder and principal instructor of the BEER course.

Moxie00
03-24-2005, 18:13
I flew fighter planes in the North American Air Defence Command in the 1960"s. It was a joint USAF and Royal Canadian Air Force command. Our job was to intercept Russian bombers over the artic or nothern Canada before they could bomb New York, Hot Springs, Moose Jaw or any other civilized place in North America. Most of our missions were in the artic winter and it was so long ago that our fighters were still made of stone, metal jet fighters came later. We did have alot of winter survival training which then consisted of being dumped in some place where it was twenty below with a down sleeping bag, some fire starter cubes, and 5 or six panels of an old parachute with the lines attached, and the same amount of food we carried in a tiny survival pack. Two or three days later the instructors would come and find us. We had no radios but they did fly over and we would wave to let them know we were alive. Some lessons I remember our instructors taught us. Get in the bag naked, clothes will constrict your blood flow if they bind. Put your clothes by your feet in the sleeping bag, your body heat will dry them and they will help insulate your feet. A wool cap was ok but it wasn't an issue idem for us. Always evacuate your bowels and bladder before going to sleep as your body shouldn't have to work to keep a bunch of poop and pee warm. However' just before getting into the bag drink lots of water so it would be in your system to help warm you and by the time it reached your blader it would be time to wake and throw more wood on the fire. Of course once we all learned this good stuff about winter survival Viet Nam came along and all that training did us very little good in the jungle.:rolleyes:

dougmeredith
03-24-2005, 21:46
Not quite - anything your body has to do requires calories.

True.


Calaories keep you warm.

*Burning* calories keeps you warm. Heat is a by-product of this process.


The more calories you burn over the course of the night, the less likely you likey you are to have enough calories to sustain you.

The more calories you burn overnight, the more heat you produce, and the warmer you will be.


If your fuel tank is running low you WILL get cold.

Your body has enough fuel to sustain you for weeks. Now if your body enters starvation mode, your matabolisim will slow, you will burn fewer calories and you will be colder.

I suspect that eating keeps you warm not because it provides fuel, but because digesting *consumes* calories and this produces heat.


To a certain extent..but if you bundle up to the point that you have no dead space in your sleeping bag, you will not be warm.

I don't understand the physics of this. If I add insulating layers such as clothes inside my bag to the point that I displace esentially all air in the bag, but I don't compress the bag, I will be warmer.


But,ever wonder why in military cold weather training the powers-that-be- make the soldiers sleep in the nude?

Not really. The fact that a group of people claim something doesn't make it so.

Doug

Panzer1
03-24-2005, 22:30
Get in the bag naked, clothes will constrict your blood flow if they bind.
I would never want to take off all my clothes in a winter situation. It's just too cold to do that.

Panzer

Panzer1
03-24-2005, 22:47
Dougmeredith srote: "I don't understand the physics of this. If I add insulating layers such as clothes inside my bag to the point that I displace esentially all air in the bag, but I don't compress the bag, I will be warmer."

You will never displace all the air in a sleeping bag. There will always be enough air spaces to insulate. The air spaces may be very small and exist only between the indivudal threads in your clothes. The air spaces do not need to be big to insulate.

Panzer

icemanat95
03-24-2005, 23:45
I would never want to take off all my clothes in a winter situation. It's just too cold to do that.

Panzer

The reason I don't take off all my clothes in a winter situation is real simple...you never know when you might need to un-ass the campsite fast. The more clothes I have to put on on my way out delays my departure and potentially endangers me. Also, what happens if I don't have time to get dressed before hauling butt? Stark naked running for cover or long underwear and down booties carrying my boots and pack as I run? Which would you prefer?

A lot depends upon your particular situation. In an alpine/mountaineering situation, you do everything you can to minimize futzing around. You want to be able to get up and get gone in the shortest amount of time possible with the least amount of screwing around. If you are operating in lowlands where the conditions are safer and more controlled, then you have the luxury to spread out and seek maximum comfort. I have yet to find warmth a problem using the alpine mode as my winter bag is rated for truly frigid conditions. Most often my problem is too much warmth and is addressed by opening up the bag and letting in some cold.

On another note...you aren't warming your pee in your sleeping bag. Your body generates it at body temperature from moisture and waste in your system that is already at body temperature. At worst all your body is doing is maintaining its temperature, which isn't a big deal since its got to maintain the temp of all the flesh around it. The difference between a cup of urine and not, is pretty much insignificant. If you are in such bad general condition that you need to worry about that, it doesn't matter anyway because you are well and truly screwed. You will certainly lose more body heat opening your sleeping bag to pee into your pee bottle than you would spend keeping that pee at body temp internally. Not to mention the fact that that pee is taking body heat with it as it goes so you are losing however many calories it cost your body to raise that cup of urine to 98 degrees in the first place.

Panzer1
03-25-2005, 01:47
The reason I don't take off all my clothes in a winter situation is real simple...you never know when you might need to un-ass the campsite fast.
Yea, I agree with that. I even worry when I take my boots off.

Panzer

Mags
03-25-2005, 02:31
>> *Burning* calories keeps you warm. Heat is a by-product of this >>process.

I think you are splitting hairs at this point. And you are enjoying it. :D
Fine..but where you do get the calories to consume and burn. From eating.

You go winter camping with me and I'll eat some pasta with cream sauce and olive oil. You have nada. See who stays warmer. You can tell me that I'm not really staying warm because of eating. You'll be right...but I'll be warm because my body is consuming calories.

'Nuff said.

>>I don't understand the physics of this. If I add insulating layers such as >>clothes inside my bag to the point that I displace esentially all air in the >>bag, but I don't compress the bag, I will be warmer.

Tell you what..I'll wear my down jacket (in a cold dry environment, naturally) that warms me up because it essentially a garment made of airpockets between down. You wear a fleece. Who is warmer?

I agree 100% on one point- if the bag is too big, you will get too cold. However, if you wear enough clothing to displace all the warmth (unlikely) you are also probably decreasing your circulation and decreasing the loft.
How's the bag working now? Also (and this statement is more directed to Iceman), I never said to sleep nude in the bag. I suggested switching to a spare pair of DRY long underwear before going to bed...just like Iceman does.

Also, Iceman is right: Yes, maintaining the temp (sorry..I said "warming up".. gotta be careful to be precise here. ;) ) does not use a significant amount of calories. But why warm up...er excuse me, maintain the temp of the pee and poop if you don't have to?

Do you really sleep well with an aching bladder? I sure as heck don't. With the exception of people on this thread, every experienced winter camper I know carries a pee bottle and uses it in in their bag. (Aim well!) Again..common sense. Do you sleep better or worse with an aching bladder? Perhaps I am not hard core. I HATE getting woken up because I have to go to the bathroom at 2am and don't want to get out of the bag. What can I say..I'm a wimp and will just use a pee bottle (carefully!) in my bag. ;)

Finally, look where I live. I camped in a snow cave at 11k feet last weekend. Woke up to two feet of snow. Not exactly low valley camping. :) Am I an expert? Heck no. Am I an experienced Colorado and New Hampshire winter camper. Heck yes. (Mind you that and a buck gets me a cup of coffee....)

bogey
03-25-2005, 05:36
Years ago, I talked my wife into going camping, not packing, mind you, but fully loaded car camping, in March. Then, I was able to persuade her that with our bags mated, and "minimal" clothing we'd snuggle and stay warmer. Ha!

all night long she was yowwing on me to stop breathing, 'cause I was sucking cold air into the bag. Well, guess she was justified sort of, the next morning there was ice on our tent. 30 years later we can both sort of laugh about it now.

Mags
03-25-2005, 11:11
Years ago, I talked my wife into going camping, not packing, mind you, but fully loaded car camping, in March. Then, I was able to persuade her that with our bags mated, and "minimal" clothing we'd snuggle and stay warmer. Ha!



Last year, my girlfriend at the time and I went on a backcountry hut trip. Fireplace, only two miles or so from the trailhead, easy terrain. Wht can go wrong? :)

Did I mention she grew up in Florida? That this was only her 2nd winter ever? Oh yes..and storm blew in at the exposed trailhead?

Long story short: We were nice and toast in the hut....however the relationship cooled off considerably. ;) (We did get back together this summer....but we broke up again recently. Deja vu all over again as Yogi Berra would say!)

Moxie00
03-26-2005, 10:54
Take my word, I've reeen there, it is only cold for a minute. Another thing we had to do as part of survival training was a real fun exercise. They would cut a hole in a frozen pond and have us jump in with full gear, clothing and with an open parachute to get tangled up in. We had 45 seconds to a minute to get out before the cold made us too numb to use our hands; 10 minutes until death. ( the instructors had wet suits and there was a heated van if anyone failed). When you got out of the water you stripped , took a compressed down bag out of it't waterproof bag, and got in it to warm up. Most people recovered in about 10 minutes. People in nothern Europe who use saunas run naked through ths snow and it never bothers them. If you have a warm place or a sleeping bag to let you re-warm your body being naked or partially naked in the winter can be a cool experience.:banana :sun :sun :sun :sun :banana

dougmeredith
03-29-2005, 09:44
I think you are splitting hairs at this point. And you are enjoying it. Maybe. :)


But why warm up...er excuse me, maintain the temp of the pee and poop if you don't have to?

You are talking about urine and stool at 98.6 degrees sourounded by tissue at 98.6 degrees. There is no heat loss from (or to) the urine and the stool, and no energy expended to keep them warm.

And no, I don't want to sleep with an aching bladder either! There is nothing worse than putting off getting up to pee because it is cold out, and then lying there awake because of your discomfort. On second thought, getting eaten by a bear would probably be worse, but I haven't tried that. :)

Doug

Just Jeff
03-29-2005, 12:43
(Mind you that and a buck gets me a cup of coffee....)
Depending on where you buy your coffee...

But if you had it in your bag it would keep you warm!

Mags
03-29-2005, 13:00
Depending on where you buy your coffee...

But if you had it in your bag it would keep you warm!


Ya know...I have to modify that old chestnut. Paying a buck for coffee MAY happen in a gas station..but that's about it nowadays.

Ok... "that and two bucks gets me a cup of coffee". :)

The Cheat
03-29-2005, 14:45
I've been thinking recently that the old idea to strip before getting in the bag was based on cotton clothes and old fashioned sleeping bags. In that case I think the person probably would be warmer to get those cotton long johns off and get inside that dry flannel.

But, with my current mummy bag and a nice warm set of polypro long underwear, I'm toasty.:sun

Jester2000
03-29-2005, 21:34
If you have a warm place or a sleeping bag to let you re-warm your body being naked or partially naked in the winter can be a cool experience.:banana :sun :sun :sun :sun :banana

The thought of the possibility of bumping into Moxie running around naked is enough to make me never winter camp ever.

WalkinHome
03-29-2005, 21:50
Much better to have big as life pictures of Billville Butts facing you at Traildays eh?