HYPOTHERMIA
Layering is a part any system. But there are other tricks.
COLD-

C = clean. Stay as clean as possible and keep your clothing as clean as possible.

O = Overheat. Prevent overheating by dressing in layers. Remove layers when needed.

L = Layers. See above, but also have layers you can add when needed in camp.

D = Dry. Staying dry is 50% or better of the battle.

Also staying out of wind or wearing clothing that can block the wind, carrying a hot water bottle to bed, eating high fat foods before bed, going to bed with an empty bladder, using a pee bottle, etc. All little tricks of the trade.

As to bulky clothing issue. My system is this:
Temps above 60:
Wear wicking t-shirt, micro-fiber underwear, nylon shorts, running socks, and have an extra set of socks and underwear in my pack. I also have a rain suit that has pants, bottoms, Sealskins, and Gortex® mittens. If the weather spikes down or gets wet, this does the trick.

Between 40-60:
Add an extra pair of socks, long johns, a knit hat, and some fleece gloves. Very little extra bulk. I have found that the heavy weigh brown polypro underwear the Army issues is just as good and a lot cheaper than some of the high tech high end stuff.

Below 40:
Add a field jacket liner and field pants liners to wear under a rain suit. Adds better insulation than the same weight of fleece and compresses better. I also add a polypro neck gator to turn my knit hat into a balaclava, an extra set of warm wool socks, and some fleece mittens to wear under the rain mittens.

It ain't a lot of bulk or weight using a layering system similar to this.

My experience with hypothermia and those that get it is that it usually happens above freezing. The standard temperature is in the 40s when it is wet. The victim isn't always wet either. Hypothermia can happen as high as the 50s.
SGT Rock

Dry clothes
The best way to prevent hypothermia is to ALWAYS have something warm and dry to put on when you get to camp and having a dry sleeping bag to crawl into. When you're hiking, it's not so much of an issue what you wear as long as it's not cotton because the hiking will keep you pretty warm.
Jackiebolen

If you really want to go as light as possible, the sad answer may be yes. The lightest stuff out there is likely more expensive. Whether you need to have that many layers is another question. If you're doing winter hiking, chances are you'll end up with a little more weight or bulk no matter what. But you can manage in the 20s without needing too many layers or expensive stuff. Just make sure that when you get to camp you have a good sleeping bag to curl into though, it's easy to stay warm while hiking but not so easy when resting. Having said that, the folks with lot of experience in winter hiking will surely have better advice.

A wool hat will definitely make a world of difference in keeping you warm. Keeping your head warm will likely have you feeling 100% better in cold weather. It sure saved my ass during some cold nights.
Rocket 04

1 Always change your shirt when you get to camp, the one you have on will be damp from wear your pack, and as soon as you stop you will notice it robbing your back of heat.

2 Put on a fleece or wool sweater to, this will very important to conserve body heat.

3 After I did the above and my bedroll setup in the lean to or tent, and my meal cooking I would change my socks, let the feet breathe a second and pout on dry socks.

4 I carried a wool cap and gloves, did not always wear them, but as soon as I got into camp I would don the on. i also used them to regulate my body temperature, when I would start getting warm I would off the gloves, and warming I would take the cap off from time to time.

5 As said above wear layers when you start to get warm, shed a layer at a time.

6 Dry; a dry and warm sleeping bag is very Important, if you are getting chills during the day, call it a day set up camp and get in the bag for a while you will warm and quickly. Its better to do low miles today than none ever more.
Take-a-Break

First let me say, from experience, Hypothermia SUCKS!!!!

The best thing you can do is to keep your wits about you, dress as warm as you reasonably can (in layers as mentioned, as much weight as you are willing to carry) BUT, be prepared to stop, set up your shelter, & get warm however you can, usually by getting into your sleeping bag. Be prepared to stop before the Hypothermia gets a hold on you, set up your shelter, & get warm however you can, usually by getting into your sleeping bag.

I supposedly "Know better" as I have fairly extensive medical training, yet I have been caught by the beast TWICE! Very embarrassing, fortunately I survived both, the last one because I happened on some other hikers at the Rich Mt fire tower who saw My condition & helped me set up camp (insisted actually) & got me into my warm sleeping bag. I protested, but was outnumbered, once I was warmed up, I saw what was happening. After cooking dinner, & getting warmer, I realized I may well have died on the AT, I was that bad.

I don’t know exactly what my saviors saw: The temp seemed warm, and I heard later from my new friends it didn’t drop below 50 that day. All I remember is something to the effect of "You don't look so good". I wasn't soaking wet, just damp inside my rain jacket. As I said, I didn't feel cold, at least not until I was warmed up, then I thought "OH! I was cold!". Perhaps I was blue? Or extremely pale? Knowing my mental condition (In hindsight) perhaps I looked dazed? That was over a year ago, and I still feel those people saved my life, wish I knew who they were.
Hypothermia is a deceitful beast, first you are cold, but keep hiking, then slowly your thought processes slow down, then you FEEL warm, "OH, I'm OK now" is what I thought at this point both times. All I felt at this point was exceptionally tired. I was almost to the point (about 1 more mile of hiking I think) of lying down in the middle of the trail & going to sleep; possibly forever, yet I wasn't aware of being cold. Both times it was raining, but not very cold, about 52f, I was wearing a rain jacket.

So; Carry what you want, be alert!! Probably carry/wear: Poly pro long underwear (tops & bottoms) a medium weight jacket (to suit YOUR temp range) a extra pair of socks or 2, the socks can also double as mittens, I like wool, a wool or fleece sweater also doubles as a pillow. Wear a hat! Avoid COTTON! A cotton shirt takes 6 weeks to dry (not really, but it will seem so). Stay dry! This may mean that you should hike cool, to avoid/reduce sweating, in order to stay warm when you stop. Be aware that when you stop shivering (as I had last time) That is a BAD sign, a VERY BAD sign, so stop & get warm NO MATTER WHAT!
Doctari.

Couldn't help but post an entry to this thread. Reason being ...that I slipped into hypothermia last year on my thru-hike and it wasn't one of those real obvious situations.

It all began as I and 2 other hikers hitched out of N Woodstock, NH last September. Something I had eaten for breakfast didn't agree with me but I figured by drinking a lot of water I could "hike it off", so to speak. We got a ride out to the trail crossing and began our climb up towards Franconia. Instead of getting better I got more and more nauseous. I told the other two hikers to go ahead and that I was going to take it easy and I'd meet them at the top. The nausea turned into cramps and I finally decided to just sit down and take a little rest. It was early in the morning. The weather was clear and cool but not really bone chilling cold. In response to the nausea and cramps I began to perspire heavily. My clothing became damp from the sweat and the evaporation caused by the wind brought about a rapid decrease in my body temperature. Within 5 minutes or so I got a bit dizzy and lightheaded and decided to just lay down on the ground off to the side of the trail. As a former paramedic ...I knew this wasn't normal and called out for the other 2 hikers. I went into shakes and shallow rapid respiration. Lucky for me, the other two hikers ran back down the hill and, noticing what was happening, took rapid action. They got me out of my wet clothes, dug out my sleeping bag and wrapped me up in it. After about 10 - 15 minutes my core body temperature was back within normal range and I began to feel more like myself. I was eventually able to hike back down the hill on my own power and hitch back into N Woodstock, where I spent the rest of that day just relaxing and counting my lucky stars.

So ...as can be gleaned from the above, hypothermia doesn't necessarily occur in freezing temperatures and amazingly enough there a lot of contributing factors to a hypothermic episode. As it all turns out, when I returned home after summitting Katahdin, I found out that I had hiked the entire trail with fairly bad kidney stones and what happened that morning was a byproduct of an acute kidney stone attack.

Bottom line is that I was lucky. While I'm at it I want to publicly recognize those 2 hikers (FireFeet and ChickFlick) for responding quickly and appropriately to my situation and essentially warding off what could have developed into a life threatening situation. I owe them a lot and will always credit them with having saved my life and my hike.

Two kidney stone operations later and healthy again ...I remember that day like it was yesterday. We talk a lot about hypothermia in the paramedical circles but until you are a victim yourself it is hard to fully grasp how fast it occurs and how helpless the victim is (despite having a medical background) to help themselves once hypothermia sets in.
Footslogger

The worst part of Hypothermia is that one of the first stages is a lessening of the blood supply to the brain. In short, you start to get stupid (OK bring on the stupid jokes). As if that is not bad enough, you have no idea that it is happening.

You think you are thinking normally, but you are not. Unless you survive it, like Footslogger, it's hard to imagine. I got off a Harley once, was wet and cold, but felt fine. I said something to a friend. He knew I had not been drinking, but he told me I did not make sense and was slurring my words (again with your jokes). I was in an advanced state of Hypothermia and felt fine. Remember, if you stop shivering but are not in a warm place you are in trouble, you just don't know it yet.
Blue Jay

My hiking buddy and I watch for the -umbles and a suggestion I have seen is to ask a less than easy math question (or other topic). Just something that takes a little thought to see if the person is all there. I would expect that if you are with someone you know well that you could spot something wrong with them, but I found Doctari's account interesting because the rescuers became aware of his condition without knowing him.

Good point by BJ about the shivering.
Alligator

-umbles
Grumbles - becomes irritable and cranky
Mumbles - doesn't talk much or clearly
Stumbles - falls more frequently
Bumbles - can't manage to solve problems, such as opening a pack and getting into a sleeping bag.

You will notice that these all involve the brain. Hiking alone in the cold puts you at risk of having to figure out you are in trouble with a brain that is impaired from the get-go.

Shivers may be the best symptom to let you know you are getting into trouble, but the -umbles frequently hold sway.
Orange Bug

Frostbite and Hypothermia
Some points to stress about Hypothermia... It happens when you least expect it, so never let down your guard thinking it is to warm to get hypothermia. Born and raised in Alaska, the only time I have gotten hypothermia (and not to bad, only to the point that my thinking capacity was lowered and I stopped shivering) was in the Florida Keys. I thought Florida was too warm to get Hypothermia, so I wasn’t prepared.

Another point... DO NOT drink alcohol when it is cold out. I have heard of a countless number of deaths from people ridding out, fully prepared for cold weather on their snow machines, drinking as they were setting up camp, and dying from hypothermia without using any of their cold weather gear. You do not feel or think of the cold weather the same when drinking. DO NOT do it.

Drink a LOT of water when it is cold, your body can always operate better when hydrated. And soda does not hydrate you. If you start feeling cold immediately get warm somehow. Drink warm water while walking, layer up more, prevent being wet at all costs, and all that common sense. But, if someone starts showing symptoms of hypothermia, ACT QUICK!

Get the person into a tent (or shelter) strip them naked, (if wet. Editor) get them into a sleeping bag, WITH ANOTHER PERSON who is not hypothermic. You want to warm their inner core, but not too fast, too fast WILL kill them. Give them hot water and liquids to drink, but not too many. Get help.

Careful planning and you should never have trouble with hypothermia. And for those frostbitten fingers... swirl them around your head in a windmill motion. It will get blood to your fingertips and warm them up. For the feet, just get to a warm place and massage them, you just have to live through the pain, it will end.
Pink

I read some people mentioning to drink warm fluids. Along with this, if at all possible (assuming the person can get it down) the person to try to eat as much simple carbohydrates as possible. Carbs are the fuel that most quickly transforms into heat and energy.
Bloodroot

I agree with the folks that say sleeping naked, or close to it, inside the bag is warmer than sleeping with thermals on but the downside is when the morning comes and you must put all your clothes back on. Maneuvering inside the bag can be rather awkward and so it becomes a speed-fest trying to put everything on again while hoping to maintain some semblance of that oh-so-toasty feeling of the sleeping bag. If you are getting cold inside your bag and you've already stripped naked, drink a half liter of water or so and you might very well warm up. I don't know the why, but someone told me that and once while I was shivering inside my bag and thinking at 1am of bailing on the trip altogether and hiking out under headlamp, I drank a bunch of water and that sure helped me to warm up. On the naked side, another winter outing had me sleeping in damp thermals and I was getting chilly. So much so I decided to get naked and see if that would help and it did.

Of course the warmest winter sleeping is to have two bags that mate together. Speaking of which, if you're a homophobic guy, get rid of any such stupidity if the circumstances get dire enough. Because you're going to spoon and massage the hell out of the dude (or him you) who's about to or already has gone into shock. Then gloss over that part of the story when you get back home.

Sleeping in a snow cave is a rather warm affair. You're out of the wind and the surrounding temp is around 30 degrees. Plus it'll warm up a little, some of the snow will melt and drip on your stuff and you can etch snow animation on the walls to pass away the time. The downside being it's a rather wet undertaking digging one.

Oh yeah, and having a piss bottle handy is worth it if you'd rather not go through the whole dressing process to drain the vein in the wee hours of the morning. Just tape the hell out of it so there's no mistaking the bottle and be kind enough to empty it after use if sharing. For women, they can use the freshette, a feminine shaped funnel... more like a detachable penis that even allows them to pee standing up while in the elements without having to hang their ass out in the wind. Speaking of which, there's the rainbow zips on some pants that allows you to drop a load while minimizing the exposure. This can sure come in handy, especially if you're wearing a harness. Just be sure it's zipped up before you glissade...

(Editor’s note: if you follow the advice in the following paragraph do so with EXTREME CAUTION!!)
If you want to go in style while winter camping in a tent, buy one of those hanging stove contraptions. Fire that puppy up in the morning and let it heat both your water and tent up while you're snuggled warmly inside your bag. For melting snow, the XGK (not a hanging stove) is the best. Your own personal jet engine.
Pencil Pusher

(Editor’s note: if you follow the advice in the following paragraph do so with EXTREME CAUTION!!)
Hey, it is amazing how much heat you get in a tent off a single candle! I have done that - very carefully - in a candle lantern. It was downright warm in that tent.
Stickman

Hypothermia is serious stuff...
It's amazing how many hikers I see, mostly day or section hikers, who wear cotton items, and this includes jeans. Cotton in winter is a Killer, period. No hiker should have on any item made of cotton. You can get good winter wear, even at second hand stores. I've purchased silk, polypropylene and wool items there. Hikers should also be careful with down sleeping bags and clothing. Wet down will NOT keep you warm, and is hard to dry. Experience will keep you alive, get it safely.
Ridge

The idea that sleeping naked is warmer than with clothes is the trail version of an urban myth that goes back 20 some odd years. It violates some basic principles of physics and thermodynamics. The insulating value of clothing (and sleeping bags) is measured in units called a clo. Clo values are additive, just like R values are. A naked body has a clo of 0.0, typical clothing that you would wear in the winter (long sleeve shirt, heavier pants) has a clo of 1.0. If you add another layer of clothes the total clo value increases. Add a sleeping bag liner it goes up some more.
Kncats

I've got to agree with Kncats. If I'm just standing outdoors and I get cold, I put on my down parka. I do not take everything I'm wearing off before I put the down parka on-doesn't make any sense. Where I would remove my base layers is if I've been hiking all day and my clothes are sweaty. After I've set up camp and have stopped sweating, I can take my sweaty clothes off and put dry ones before I get cold or before I get into the sleeping bag. If you're on a multi-day trip your sleeping bag could get progressively wetter as sweat enters the bag and freezes. This makes the bag heavier and less effective as an insulator. I've read stories of old-time arctic explorers whose sleeping bags ended up weighing 50 pounds after a long stay in the cold. Also as the sweat evaporates, your body is going to be cooled by the process. Under extreme cold conditions is where vapor barrier clothing as a first layer actually works.

I remember in 1987 getting to the top of Roan Mountain, in a storm, after dark, with 6 inches of snow on the ground and staying in the cabin. I took off my wet polypro shirt and put on dry clothes before getting into my sleeping bag. The temps hit 20 degrees that night and when I got up the next morning my long-sleeved poly shirt was frozen solid. It took me a half-hour to get up the courage to put that back on before I started hiking that day.
The Old Fhart.

Summation:

Hypothermia can kill. It does so many times a year, even right here in the “good ole U S of A”. Even in Sub Tropical Florida.

Hypothermia is sneaky. It can attack you slowly, so slowly you don’t even notice. Or it can attack quickly, so fast you don’t have time to react.

Staying dry helps. Staying aware, of yourself and those around you, can save a life. Getting warm/dry quickly will save a life.

Hypothermia should not be confused with frostbite. They are two different things. You can have frostbite, but not be hypothermic. Or you could have hypothermia but not have frostbite. Or, you could have both. Frostbite (usually) requires below freezing temperatures, Hypothermia DOES NOT.

If you are hypothermic: Stop! Get warm! Eat something! Drink plenty of fluids before, during and after, but bear in mind: cold fluids can increase the risk of hypothermia.

You can die from hypothermia shortly after saying: “It’s FIFTY degrees out, I can’t be hypothermic!”

A "Pee Bottle" reduces the time spent out of your nice warm sleeping bag & shelter. Remember that it takes quite a bit of energy to keep the liquid in your bladder warm, so by removing that un needed fluid, you may stay warmer, longer.

Alcohol is to be avoided; it causes the blood vessels to dilate, especially in the skin, causing you to feel warm but in fact accelerating the heat loss.

You should also avoid any other diuretics like: coffee, tea, soda (& for me at least: apple juice) you do not want to get dehydrated.

Great article ...thanks for pasteing it together.

Pan

I know you were putting together some information from other posts, I reccomend that you change the spacing so it seperates some parts out a little. And, if someone like me has two posts in the reccomendations, you could add them together to get a single section
Example

Hypothermia
Layering is a part any system. But there are other tricks.
COLD-
C = clean. Stay as clean as possible and keep your clothing as clean as possible.
O = Overheat. Prevent overheating by dressing in layers. Remove layers when needed.
L = Layers. See above, but also have layers you can add when needed in camp.
D = Dry. Staying dry is 50% or better of the battle.
Also staying out of wind or wearing clothing that can block the wind, carrying a hot water bottle to bed, eating high fat foods before bed, going to bed with an empty bladder, using a pee bottle, etc. All little tricks of the trade.
As to bulky clothing issue. My system is this:
Temps above 60:
Wear wicking t-shirt, micro-fiber underwear, nylon shorts, running socks, and have an extra set of socks and underwear in my pack. I also have a rain suit that has pants, bottoms, Sealskins, and Gortex® mittens. If the weather spikes down or gets wet, this does the trick.
Between 40-60:
Add an extra pair of socks, long johns, a knit hat, and some fleece gloves. Very little extra bulk. I have found that the heavy weigh brown polypro underwear the Army issues is just as good and a lot cheaper than some of the high tech high end stuff.
Below 40:
Add a field jacket liner and field pants liners to wear under a rain suit. Adds better insulation than the same weight of fleece and compresses better. I also add a polypro neck gator to turn my knit hat into a balaclava, an extra set of warm wool socks, and some fleece mittens to wear under the rain mittens.
It ain't a lot of bulk or weight using a layering system similar to this.
SGT Rock
and

My experience with hypothermia and those that get it is that it usually happens above freezing. The standard temperature is in the 40s when it is wet. The victim isn't always wet either. Hypothermia can happen as high as the 50s.
SGT Rock
Change to:
-------------------------------------------------------------
From SGT Rock: Layering is a part any system. But there are other tricks:

COLD

C = Clean. Stay as clean as possible and keep your clothing as clean as possible.

O = Overheat. Prevent overheating by dressing in layers. Remove layers when needed.

L = Layers. See above, but also have layers you can add when needed in camp.

D = Dry. Staying dry is 50% or better of the battle.

Also staying out of wind or wearing clothing that can block the wind, carrying a hot water bottle to bed, eating high fat foods before bed, going to bed with an empty bladder, using a pee bottle, etc. All little tricks of the trade.

As to bulky clothing issue. My system is this:

Temps above 60: Wear wicking t-shirt, micro-fiber underwear, nylon shorts, running socks, and have an extra set of socks and underwear in my pack. I also have a rain suit that has pants, bottoms, Sealskins, and Gortex® mittens. If the weather spikes down or gets wet, this does the trick.

Between 40-60: Add an extra pair of socks, long johns, a knit hat, and some fleece gloves. Very little extra bulk. I have found that the heavy weigh brown polypro underwear the Army issues is just as good and a lot cheaper than some of the high tech high end stuff.

Below 40:Add a field jacket liner and field pants liners to wear under a rain suit. Adds better insulation than the same weight of fleece and compresses better. I also add a polypro neck gator to turn my knit hat into a balaclava, an extra set of warm wool socks, and some fleece mittens to wear under the rain mittens.

It ain't a lot of bulk or weight using a layering system similar to this.

My experience with hypothermia and those that get it is that it usually happens above freezing. The standard temperature is in the 40s when it is wet. The victim isn't always wet either. Hypothermia can happen as high as the 50s.


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Anyway, it is just a thought.

Ditto, while it is not as difficult to read as ALL CAPITAL LETTERS, the use of Bold and Italics would really help readers absorb this huge and important article.

That better? :)

It is better, but something still doesn't "feel right" with me. Let me study on it for a day :D

Keep up the good work.

It should start with what Hypothermia is, how to recognize it, and how to treat it. Next should be prevention by recognizing situations that breed hypothermic danger, prevention by wearing/doing the right things.
Super idea for an article, Doctari!

Great thread. From personal experience (AT 2003 going up Franconia) ...and this is coming from someone with considerable medical experience, you need to stress that the symptoms are insidious and can be rapid in onset. I knew what was happening but still found myself unable to react in time.

But, the bottom line (as you point out well) is prevention with proper clothing and hydration and then second is rapid recognition of the signs/symptoms and what to do if it hits.

'Slogger
AT 2003

Great article!! I agree with TJ about the format. It may also help if you change the font of your replies so that the transition is unmistakable. I had no problem with it but it may be an issue for a newby.

As of now, I'm off work all day Thr.
Will work on a better introduction by then, and hopefully any more suggestions can be ironed out at that time.

I think that a "definition of hypothermia" is a good idea, I'll get that together.
Footslogger (or anyone :) ) If you could e-mail some suggestions/definitions if you have any. It's been a, , , , weird month, the brain ain't doin it's job as well as me would like it for to do :bse

Mt Hippie:
"It may also help if you change the font of your replies so that the transition is unmistakable. I had no problem with it but it may be an issue for a newby."
Like I said, brain ain't workin, I don't think I get what you mean. Example(s)? And type slowly, I'm not reading very fast anymore, LOL.

Thanks all!!!!

Example: Kncats statement in one font
Your reply in another font

I may not be using the correct computer terminology. My brain sometimes arrives at the computer a few minutes or even hours after my body. :)
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The idea that sleeping naked is warmer than with clothes is the trail version of an urban myth that goes back 20 some odd years. It violates some basic principles of physics and thermodynamics. The insulating value of clothing (and sleeping bags) is measured in units called a clo. Clo values are additive, just like R values are. A naked body has a clo of 0.0, typical clothing that you would wear in the winter (long sleeve shirt, heavier pants) has a clo of 1.0. If you add another layer of clothes the total clo value increases. Add a sleeping bag liner it goes up some more.
Kncats

I've got to agree with Kncats. If I'm just standing outdoors and I get cold, I put on my down parka. I do not take everything I'm wearing off before I put the down parka on-doesn't make any sense. Where I would remove my base layers is if I've been hiking all day and my clothes are sweaty. After I've set up camp and have stopped sweating, I can take my sweaty clothes off and put dry ones before I get cold or before I get into the sleeping bag. If you're on a multi-day trip your sleeping bag could get progressively wetter as sweat enters the bag and freezes. This makes the bag heavier and less effective as an insulator. I've read stories of old-time arctic explorers whose sleeping bags ended up weighing 50 pounds after a long stay in the cold. Also as the sweat evaporates, your body is going to be cooled by the process. Under extreme cold conditions is where vapor barrier clothing as a first layer actually works.

Correct me if I'm wrong, but wouldn't the heat trapped between your skin and the bag warm you faster without a layer or two of clothing in between? This assumes that the insulating ability of the bag is greater than your clothes. It seems to me that I warm up quicker when I get in my bag in my skivvies vs. in my clothes. Even when here at home, if I'm cold I take off my pants and get in my bag to warm up: works better than getting in with pants on.

Or should I just chalk this up to another strange phenomenon? :-?

Hypothermia is strange, all right. Two winters ago I was sectioning the Smokies when I stopped on Thunderhead Mtn to watch the snowfall for about half an hour. I wasn't wearing anything on my head and was only wearing a windjacket. The chill February wind was blowing up there, and after half an hour or so of standing still I moved on to Spence Field shelter a couple miles away.

Just before dark I came to the shelter junction, and I looked right at the sign saying SHELTER --->. It didn't register in my noggin. I kept walking on the AT, until about a quarter mile later when I finally thought to myslef that the shelter may have been back at that turnoff. I turned around (fortunately) and went back to that sign, and this time it clicked what I was reading.

Example: Kncats statement in one font
Your reply in another font

I may not be using the correct computer terminology. My brain sometimes arrives at the computer a few minutes or even hours after my body. :)
--------------------------------------------------------------------------

The idea that sleeping naked is warmer than with clothes is the trail version of an urban myth that goes back 20 some odd years. It violates some basic principles of physics and thermodynamics. The insulating value of clothing (and sleeping bags) is measured in units called a clo. Clo values are additive, just like R values are. A naked body has a clo of 0.0, typical clothing that you would wear in the winter (long sleeve shirt, heavier pants) has a clo of 1.0. If you add another layer of clothes the total clo value increases. Add a sleeping bag liner it goes up some more.
Kncats

I've got to agree with Kncats. If I'm just standing outdoors and I get cold, I put on my down parka. I do not take everything I'm wearing off before I put the down parka on-doesn't make any sense. Where I would remove my base layers is if I've been hiking all day and my clothes are sweaty. After I've set up camp and have stopped sweating, I can take my sweaty clothes off and put dry ones before I get cold or before I get into the sleeping bag. If you're on a multi-day trip your sleeping bag could get progressively wetter as sweat enters the bag and freezes. This makes the bag heavier and less effective as an insulator. I've read stories of old-time arctic explorers whose sleeping bags ended up weighing 50 pounds after a long stay in the cold. Also as the sweat evaporates, your body is going to be cooled by the process. Under extreme cold conditions is where vapor barrier clothing as a first layer actually works.


Ah! I see!

Terminology was fine, it's my oldtimers at work :datz

deleted deleted

I worked part time for 17 years aw a whitewater raft guide on the cold rivers of Maine. Because I was a trip leader I also had to have training and work as an E.M.T. I was proud that I almost always spotted hypothermia symptoms shown by my customers in the very early stages and was able to treat it before it became advanced, Some of our worse cases came on cold rainey days in the summer when a client was dressed in cotton and the temperature was around 50 degrees. We actually had very few cases in April when the water was high and there was still ice in the river because people dressed for the occasion in wet suits, nylon and wool and everyone wore a wool cap. A large percentage of your heat loss is through your head and I've seen even a baseball cap turn the early stages of hypothermia around. What amazed me was that I didn't even realize that I was well on my way to a serious case of hypothermia on my thru hike in 2000. It was a rainy, foggy day, there was a little sleet, and I was trying to reach Brown Fork Shelter. I was cold, wet, and exausted from what seemed like an endless steep climb I did not expect. When I got to the shelter I just did the normal things one does. I took off my boots, unpacked my pack and inflated my pad and set up my sleeping bag. "Pat from Maine" was there and she was the one who spotted that I was entering the second stages of hypothermia, I had no idea. She took control of me at once, had me strip off some of my wet clothes, gave me a snickers bar, and told me to get into my sleeping bag. In about an hour my body warmed up, I was fine. It is amazing to me that someone like myself who was trained to spot hupothermia, had years of experience dealing with it, didn't recgonize it when it happened to me.

Well, I feel a little less Stoopid, 2 other EMTs have been caught by the beast. We are supposed to know better, have all that training & stuff. And, Moxie has seen it's effects first hand.

Lesson here I think: ANYONE CAN GET CAUGHT BY HYPOTHERMIA! The symptoms may be obvious to others, but not to the victum.

BTW: When I get off work PM today, Ill be posting from my Medic books the definition / description of Hypothermia. Also what to look for etc. & adding some of the new comments from y'all.

Thanks for the help gang. :D

Doctari.

The worst part of hypothermia is the brain failure. The "-UMBLES" mnemnotic is a good way to train the other guy to catch you if it happens. It is a good reason to avoid solo winter travel.

It seems that after reading the other posts from those that have suffered from close calls with hypothermia we may need to consider a couple of things.
First it is obvious that we need to take precautions to avoid hypothermia. I mean prevention should be a priority since our ability to recognize hypothermia in ourselves greatly diminishes early in the onset.
This leads me to ask how often does exhaustion or illness play a part? When we are exhausted or ill our thought process is compromised and we we often do things to help us forget or alleviate some of the tiredness and/or pain. How often could this be the first break in the chain of events that puts us at risk of hypothermia?
Sorry for the questions, but I find interesting and perhaps helpful to consider that other factors may play a part in increasing the possibility of suffering from hypothermia and at the same time diminish our ability to recognize the increased threat.

It seems that after reading the other posts from those that have suffered from close calls with hypothermia we may need to consider a couple of things.
First it is obvious that we need to take precautions to avoid hypothermia. I mean prevention should be a priority since our ability to recognize hypothermia in ourselves greatly diminishes early in the onset.
This leads me to ask how often does exhaustion or illness play a part? When we are exhausted or ill our thought process is compromised and we we often do things to help us forget or alleviate some of the tiredness and/or pain. How often could this be the first break in the chain of events that puts us at risk of hypothermia?
Sorry for the questions, but I find interesting and perhaps helpful to consider that other factors may play a part in increasing the possibility of suffering from hypothermia and at the same time diminish our ability to recognize the increased threat.


Good point. Well worth mentioning!!

My first "Event" was day 10 after a long day (#9) climbing out of NOC @ Wesser. My food intake day 9 was 1400 cal. (Yes, I counted, that day only, don't know why) Breakfast day 10 was 1 pack of instant grits, about 200 cal, I think I ate ONE candy bar that day. Didn't feel exhausted, best described as slightly tired. Fortunately for me the brown fork shelter was, by my guess, about 10 steps less than I had left in me.

Event #2: day 5, Hiked out of hot Springs, rained most of day 4, all of day 5. Yes, I was wore out!! Pushed much too hard first 4 days, and day of event. I was SO LUCKY!! On day 6 I saw where I would have collapsed had my newfound friends not stopped me. Don't ask how, but when I walked to that spot, I knew that was where I would have stopped, possibly forever. Roughly ¼ mile past the campsite.

See why I'm passionate about the topic.


Doctari.

Last Memorial Day weekend (2004) I traveled the harmless path into the floor of Tuckerman Ravine on Washington. It was a nice mid-spring day. From the mid point on up there was light snow drifting on the breeze but there was mostly sunshine with thin clouds. I kept plodding along. I always sweat a lot. I also know I didn't have the clothing I have now. I am sure it was a cotton shirt and I know it was jeans. I carried a jacket in my daypack but never felt the need to use it.

I reached the caretaker's house on the floor of the ravine (well actually took time to explore the cabins first), then pushed on to the headwall as the deck on the house was PACKED.

I made it up to the edge of the remaining snow and watched the skiers. After an undetermined amount of time watching, taking pictures, and talking to people, I finally felt cold for the first time all day.

I made my way back to the caretaker's building and went inside. That is where I saw the electronic weather station and saw it was 31 degrees with a 15 degree wind chill. I stared at it in disbelief.

I then went to sign the register and that's when I discovered that while I could hold the pen, I could NOT write my name. All that came out was a line across the page.

I went out into the sun, found a spot with no wind. Ate just about everything I had brought and drank a lot of water. In 30 minutes or so I was able to go back in and write my name.

Scary

PCM

I had the similar experience and have come up with a personal way to test my cognition and fitness for duty. I will periodically do a Mini Mental Status Exam on myself: recall the day and date, my addresses and phone numbers, recalling my 3 "items" of the day, do serial 7's or spell words backwards, identify and name (out loud) flora I pass by, and assess whether I'm a happy or an unhappy camper. I do this about 2-3 times a day if walking alone.

I sing out loud. I try skipping or picking up objects along the path.

Some of this simply provides exercise and calorie burning. Some of this lets me know of early cognitive/brain failure. When I screw up, I stop and eat something and consider early camp and extra clothing.

I prefer to do this with another hiker. It is easier to recognize problems in another, especially when conversation begins to lag.

Doctari, That is exactly what I was talking about. I think that if those that have suffered from hypothermia reverse the process in their mind they will often find that the road to disaster began before the first sign of hypothermia. We have all heard the old adtage that "cotton kills". Well could it be that mal-nutrition, exhaustion and illness are the "modern" stepping stones to hypothermia, at least for those that are experienced hikers. I know that I will often abuse my body while hiking and will fail to notice that when my body gets tired or sick my mind will be the next thing to suffer. Your article and other posts have given me reason to re-evaluate some of my habits.
Doc I understand your passion for the subject, I feel the same when it comes down to developing an understanding of where and how such problems begin. I hope that others will continue to post their experiences with hypothermia so that we all may learn from them.

Orangebug - That is a great approach to self analysing one's state of physical and mental well being. It would be especially handy for someone hiking alone. I could be wrong but I think that would be a good addition to Doc's article. Thanks for the info

heck i kinda like a little hypothermia, last spring I climbed up from fontana to mollies ridge shelter, about half way up it started to snow by the time I got to the shelter there were 5-6 inches around, I only had on hiking shorts and a poly pro shirt. my left arm not just my hand was very slow moving and I was covered in snow and wet. once at the shelter I stripped got into my bag, shivered a bit , got the stove going and made hot tea,,,i kinda like being cold.

edgy stuff...ok orangebug what is the DX?

a couple hikers I meet going up to Mollies offered me ponchos and stuff.that I refused .I had plenty of gear with me, just like the feel of cold....

I do the same up in AK...frostnipped my nose once this past winter out snow-shoeing at -28 F..but i really dig the cold.

HYPOTHERMIA


by The Old Fhart
Last edited 24 May 2005

1) DEFINITION AND DESCRIPTION
Hypothermia: From “Hypo” meaning: Low, lowered, lowering or below. And “Thermia” meaning temperature, so: Lowered (body ) Temperature.
Hypothermia Is a state of low body temperature, specifically low body core temperature. When the core temperature of the body drops below 97º (36º C) an individual is considered to be in a hypothermic state. Hypothermia can be attributed to either: a decrease in heat production (perhaps due to illness or injury, dehydration, or lack of food); or an increase in heat loss (perhaps due to; lack of adequate clothing for the temperature, wet, windy conditions.); or a combination of both.

2) HYPOTHERMIA vs FROSTBITE
Years ago you heard of people dying of “exposure.” What we used to call exposure is hypothermia. This is different from frostbite, which can only occur below freezing. Frostbite is freezing of an exposed part of the body. With frostbite the cells in the affected area freeze and the cell walls burst actually killing the tissue in that area, like nerves, skin, muscle, and capillaries. This is why you see severe frostbite areas turning black from the dead tissue. Serious frostbite can be extremely painful and require months of recovery with possible loss of fingers, limbs, etc.. Contrary to popular old wife’s tales an area of frostbite should not be rubbed as this will just cause more damage. The treatment of frostbite is similar to that of burns. With hypothermia there is no tissue damage.

Links to further info:
Frostbite treatment (http://www.emedicine.com/emerg/topic209.htm) Warning! Graphic photos

It is amazing how misunderstood hypothermia is. Basically, the human body functions over a very narrow internal temperature range. The loss of core temperature, or losing heat faster than it can be generated by the body, results in hypothermia. The body’s normal temperature is 98.6°F and a drop of under 2°F will start this process. Note that hypothermia is caused only by loss of core temperature and you could have frostbite on your hands and still not be hypothermic. Hypothermia also doesn’t require near freezing temperatures, in fact, a person with low body fat and a low metabolic rate could easily get hypothermic sitting in a swimming pool or bath at 75°F. Your body’s ability to generate heat depends on health, level of fitness, proper hydration, food, etc. Alcohol consumption will make you FEEL warm, when in reality the alcohol, in addition to clouding your judgment further (see “97°F” above), dilates the blood vessels in your skin thereby increasing heat loss (& causing that flushed feeling/look). Coffee and some other drinks are also diuretics and can cause dilation of blood vessels in the extremities and accelerate heat loss. Most cases of hypothermia associated with hiking occur in the summer months when the temperature is 40°F-50°F and you have wet, windy conditions.

Hypothermia victims can be divided into three main categories According to Core Body temperature range: mild, moderate & severe:
A core temperature between 94º and 97º F (34 – 36 C) is considered mild hypothermia.
A core temperature between 86º and 94º (30 – 34 C) is Moderate Hypothermia.
A core temperature less than 86º F (30 C) is Severe Hypothermia.

So let’s see what happens as you lose core temperature:
98.6°F- your brain functions normally
97°F - judgment starts to go; as temperature decreases so does mental ability
96°F - you begin shivering, there is loss of fine motor skills like tying shoes
94°F - coordination is failing, you start stumbling; shivering increases
92°F - shivering is severe; you will be unable to walk
90°F - shivering is convulsive; you are unable to talk; you assume the fetal position
88°F - shivering stops because the body is giving up on that method of re-warming itself
86°F and below -you are in what is referred to as a “metabolic icebox” where you may appear dead. You are unconscious, ashen gray, no perceivable pulse or breathing.

Links to further info:
Hypothermia, a complete guide (http://www.princeton.edu/~oa/safety/hypocold.shtml)
Hypothermia (http://www.dcnr.state.pa.us/forestry/searchandrescue/hypthm.aspx)

3) SYMPTIONS -WHAT TO LOOK FOR
Although the “umbles” (grumble, mumble, stumble, tumble) have been mentioned as telltale symptoms of hypothermia, keep in mind that these aren’t necessarily obvious or occur in exact order. Also, these symptoms are generally not obvious to the person who is getting hypothermic because of their depressed brain function. Almost always it will be a fellow hiker that recognizes the symptoms.

Grumble The grumbling occurs when we get irritable, but some people start out that way. What you should be looking for in your fellow hikers is a change from what is normal for them. A lot of people who grumble aren’t hypothermic, that’s just normal for them. However, if it is cold and wet and someone starts to grumble, try to figure out the cause. If it is the onset of hypothermia, take corrective measures.

Fumble As your hands get cold, there is loss of fine motor skills like those required to tie shoes. This may also be caused by localized cooling and not hypothermia.

Mumble Contrary to popular belief, this doesn’t have a lot to do with the brain. There are facial muscles that move the jaw and when they get cold and stiffen up we have trouble forming words. If you start talking nonsense then it probably is the brain that is involved.

Stumble Again, the brain is not the only thing that could cause this problem. If your legs get really cold there are two big nerve bundles in your legs that control things like foot drop, etc. If you’ve ever watched a drunk, you can recognize this staggering, flatfooted foot slapping on the floor type of gait. The inability to send and receive nerve messages from the feet are one thing that causes this problem. This could occur alone or in combination with the brain having problems because of hypothermia.

Tumble This one is pretty obvious and almost always comes after some combination of the previous three “umbles”. This is when you are getting into a really serious stage of hypothermia.

Some of the other symptoms that you may notice are the hypothermic person becoming combative, or even taking off clothing. Even well prepared hikers suffering from hypothermia have died despite having everything they needed to survive right in their pack. Don’t expect rational thought processes from someone who is hypothermic.

links to further info:
Recognizing Hypothermia (http://www.ehow.com/how_6315_recognize-assess-hypothermia.html)

4) TREATMENT –HOW DO I TREAT SOMEONE WHO IS HYPOTHERMIC?
The first thing to do is to recognize a person who is hypothermic, remove the cause, and take corrective measures. The only true way is to measure core temperature is with a special low-reading rectal hypothermia thermometer. A friend of mine who trains EMTs and is an expert in cold weather related injuries claims if you are willing to let him take your rectal temperature, you ARE truly hypothermic.

If the hypothermia is mild and the person can still walk, the best course of action is to remove the cause. If the clothes are wet, strip the person and put on dry warm clothes. If they haven’t been eating or drinking, feed them. And, most important, keep them moving. It is easier to keep them producing their own heat than for you to try to warm them by other means. This works only if the hypothermia is mild and the person can still walk. Always ambulate before carry if possible because any backcountry litter carry involves a large group of rescuers and many hours.

If the hypothermia is more moderate, keep this one thought in mind: never strip them and put them in a sleeping bag with a functioning warm person. Almost always you will succeed in creating two hypothermic people. This is a very bad idea. What you need to do is to remove the cause of the hypothermia, like their wet clothes, and put them in a hypothermia wrap or sleeping bag (see link for details). You should try to warm the core and not the extremities. Warming the arms and legs can “fool” the body into thinking it is warmer and flushing the warmer blood from the core to the extremities, further cooling the core. The last reference below shows how to create this “human burrito,” as it is sometimes called, to re-warm a hypothermic person.

If a hypothermic person is conscious and is capable of drinking (after removing the cause of the heat loss and protecting them), be very careful that the drinks you give them aren’t too hot. Because the sensation of touch and warmth is so depressed it is very easy for a hypothermic person to be burned by steaming hot liquids that a normal person could not drink. Any drinks should be tested or measured by thermometer to be no more than 105°F. Never try to give drinks or food to an unconscious person.

One last thing. Never assume that if there are no visible signs of life in a severly hypothermic person that it is too late. The experts in this field of medicine say they aren’t dead until they are warm and dead. Respiration can be near zero and the pulse rate could be 6 per minute. Because the blood supply to the extremities is basically shut down, you will get no distal pulse. The muscles stiffen up with the cold and the heart is a muscle. A severe hypothermic person who appears to be dead may just be in this “metabolic icebox.” The severely hypothermic person's heart is extremely susceptible to ventricular fibrillation, which even the slightest jolt can cause. A severely hypothermic person should never be re-warmed in the field. They must be protected from further heat loss and carefully transported to a hospital as soon as possible.

links to further info:
Mild hypothermia (http://www.ehow.com/how_6316_treat-mild-hypothermia.html)
Severe hypothermia (http://www.ehow.com/how_6318_treat-severe-hypothermia.html)
thermo-wrap (human burrito) (http://www.princeton.edu/~oa/safety/hypocold.shtml)

5) PREVENTION –FUEL FOR THE BODY
I know some of you are saying: “Hey, that doesn’t sound like any fun, how to I prevent it?” Well, to prevent it you have to know a little bit about thermodynamics, fortunately, very little. You have to understand how the body generates heat and distributes it through the body as well as how the body loses heat. Metabolism, level of conditioning, illness, drugs, alcohol, and fatigue also can play a big role in hypothermia.

First of all, the body can be thought of as a furnace, burning the fuel (food) that you feed it. The blood forms an important part of this system sending the processed fuel to the cells. Anything that compromises this flow (even restrictive clothing) will cause problems. As you get dehydrated the blood becomes more viscose, or thicker, and its ability to transport oxygen and fuel to the cells decreases. The sensation of thirst isn’t a good indication of when to drink. When you “feel” thirsty, you are already down a quart or so. The sensation of thirst is also depressed by the cold affecting the brain. This is why it is so important pay attention to staying hydrated.

Not all foods are created equal and not all fluids are either. Sugars give you a quick shot of energy but pastas, potatoes, and fats are slower burning and are best to eat before bedtime to help keep your furnace going through the night, but they require more water to digest as well. The problem with fruit juices and some energy drinks is they are too concentrated and are absorbed by the body slowly. Juices diluted about 2 to 1 are absorbed faster. Alcohol, coffee and some other drinks should be avoided. Coffee is a diuretic and can cause dilation of blood vessels allowing the extremities to radiate more heat. The effects of drinking coffee could be thought of like taking off an insulation layer.

links to further info:
Eating and drinking right (http://world.std.com/~bostonhb/docs/winterfood.html)
Vegetarian Eating and drinking right (http://gorp.away.com/gorp/activity/hiking/food/hik_veg2.htm)


6) PREVENTION –CLOTHING AND THERMOREGULATION
There are several ways the body can lose heat. The main ways are:

Conduction One way is by direct contact like lying on the ground. If you and your clothing are wet the loss of heat is up to 25 times greater than if you are dry.

Convection is heat loss due to a breeze and is known as “wind chill.” Again, if you are in damp or wet clothing, the problem is much worse. Although fleece is a good insulation layer, it is very porous and is next to useless in a wind. One way to improve fleece is to add a wind block layer. Another way is to wear a thin wind shirt over the fleece. A tent, or an enclosed hammock, would be warmer than an open-faced shelter by blocking wind and adding some insulation.

Respiration A lot of heat is lost during respiration as a combination of conduction and evaporation. Inhaled cold air is warmed by contact with the upper airway & lungs and the warm exhaled air has moisture from evaporation in the lungs if the inhaled air is dry. The drier the air, the more respiration also contributes to dehydration. Higher altitude, colder and drier air, and rapid breathing all contribute to higher heat loss and dehydration.

Radiation The rate of radiation increases as the difference in temperature between you and the air increases. Like convection, this form of heat loss can be lessened considerably by adding a layer of insulation.

Evaporation Sweating is the body’s natural way of trying to regulate our temperature when we get too hot. The amount of sweat produced by a body at rest could be about 100ml per day. With heavy exercise this could climb to 5000ml or 5 liters per day. If this moisture can’t pass through your clothing to the outside, you will get soaked.

The materials used for your clothing layers are important. Remember cotton absorbs water, loses its insulation ability, gets heavy, and should not be used as a layer. The phrase "cotton kills" says it all. The base layers should be hydrophobic, i.e., not absorb or attract water, the synthetic base layer should freely pass sweat to the outer layers and keep your body as dry as possible. Any of the layers you use should not be constrictive as this will restrict blood flow and make you feel colder. Always think of your layers as part of a “system” that has to fit together properly. When you buy your outer rainproof layer, make sure it is large enough to fit over all the other layers you could be wearing underneath it. Added features like full front zippers and "pit-zips" in jackets and full-length side zippers in rain/wind pants can make them much more versatile and easy to put on or take off. Check the references on layering for a more complete description of material options and layering.

Putting on or taking off layers of clothing allows you to bring your body’s temperature back closer to the normal range under widely varying conditions which could include wind, sun, rain, snow, or your differing levels of exertion. If you do not have the proper clothing for the conditions you are in, you are at risk of hypothermia. A popular belief is that the body tries to “protect” the core organs by shunting blood flow away from the extremities. While this is the effect, the reason is simply to prevent heat loss from the extremities. Not as much heat is radiated from the head as is commonly believed but a hat is an important part of a clothing system. Gloves are also important to prevent your hands from getting wet and cold, which could lead to loss of coordination.

Trying to prevent having to go pee in the middle of a cold night by not drinking (hydrating) properly before bed isn’t wise and can cause you to sleep colder. The old wife’s tale about it taking energy to keep the water in your bladder warm defies logic and science. One practical suggestion to add warmth is to fill a water bottle with hot water and take that to bed with you. This should be done with care because if the water leaks, then you are in trouble. My personal feeling is that you should be carrying enough clothing and a warm enough sleeping bag so this isn’t necessary for warmth.

Also, the air in the sleeping bag doesn’t hold some mystical property that make you sleep warmer when naked. The bottom line is more insulation equals more warmth. If you put on a layer of dry clothing, you will sleep warmer. One footnote should be that an equal sized volume filled with down (or any other type of sleeping bag insulation) is warmer than an equal sized volume filled with air. The reason is convection currents in the larger air areas allows heat flow. The down actually doesn’t have any insulation properties itself, it does, however, break up the possibly convection current heat losses by creating many micro pockets of air, and it is very light and compressible. Keep in mind that if down gets wet, it is useless as an insulator, and is very heavy. Synthetic insulation (like Primaloft) is much better in this regard.

links to further info:
Layering 1 (http://www.patc.net/hiking/gear/winter.html)
Layering 2 (http://www.adventurenetwork.com/cgi-bin/adventurenetwork/Layering_101.html)
Sleeping bag ratings (http://www.moonstone.com/tech_choose.htm)


7) Summation:

-Hypothermia is sneaky and can kill. The hypothermic victim is generally not the person who notices their problem.
-Hypothermia (lowered core temperature) should not be confused with frostbite (localized freezing of tissue). These are two different things. Both are serious and require immediate attention.
-If you are hypothermic, or find someone who is hypothermic, remove the cause and prevent further heat loss. Take corrective measures as described above depending on the severity and level of consciousness of the person.
-Alcohol and any diuretics are to be avoided; they will cause the blood vessels to dilate, especially in the skin, causing you to feel warm but in fact accelerating the heat loss.
-Cotton clothing is totally inappropriate for hiking: The saying “Cotton Kills” may seem over used, but cotton & cold, wet weather do not mix. Always carry extra appropriate clothing, raingear, and shelter. Be prepared.

On the UMBLES, I'd scratch TUMBLE and insert BUMBLE. This gets to the lack of fine motor eye/hand coordination and difficulty dealing with gear.

BTW, it looks great!

On the UMBLES, I'd scratch TUMBLE and insert BUMBLE. This gets to the lack of fine motor eye/hand coordination and difficulty dealing with gear.

BTW, it looks great!I prefer FUMBLE, whether TUMBLE is left in or not.

Actually STUMBLE and BUMBLE are pretty much the same (dictionary, BUMBLE-to proceed unsteadily : STUMBLE). TUMBLE is definately different than those two because you are actually falling down.

I like coming into a cabin and standing by a wood stove when I have to defrost....

I lieka good chillin ;)

WOW!

So much info. I'm gonna have to sit down & do some actual work now. :eek:

Ah well, I did volunteer to do this. :jump :p

Keep it comming.

I also am getting help from a few of the other EMTs here via E-mail. So this thing should be quite the definitive paper on wilderness Hypothermia. With definitions (Thanks Old Fhart) Examples, treatment & stuff.

We may also have to deviate into frostbite, just to have cold weather totally covered. For now tho I'm trying to save that for another article.

Doctari.

I really like how The Old Fhart laid that out and referenced the piece.

I really like how The Old Fhart laid that out and referenced the piece.

Me too,

no,

wait, , , , ,

(Doctari now enters "whine mode")

Ah man, now I has to do more work! And I was almost done :datz


Actually, That is a wonderful version. I have a few things to add, but "Damn" that was fine work, specially for an OLD GUY :D

Rock is/was right, my version didn't "Feel right", at least on a hiking forum.

Thanks Old Fhart, I really apreciate this!!!!!! Especially the links & stuff :dance

Doctari.

So do we want to go with Old Fharts or are you going to do some updates using that as a part of the article and give dual credit?

So do we want to go with Old Fharts or are you going to do some updates using that as a part of the article and give dual credit?

Sorry for the delay. Family chrisis after family chrisis, etc.

I just edited the 2 together, going to send that to OF, & back & forth. He can have credit, did the most work :p

Doctari.

I made changes to my post #25 on hypothermia after input from Doctari and others. There may be mistales because I did this quickly as I'm leaving for Trail Days in 1 hour. See you there!

I made changes to my post #25 on hypothermia after input from Doctari and others. There may be mistales because I did this quickly as I'm leaving for Trail Days in 1 hour. See you there!

Beautiful job. Much better than my version, thanks!!!

Have a good time at trail days!!

Wish I could be there, sigh.


Doctari.

An obervation / inquiry which may or may not be directly on topic.


Q1:

I have read suggestions to wear Zip-Loc bags* over the feet in cold and wet conditions - - this is usually recommended for people wearing hiking shoes with soft-uppers - - to take advantage of the Vapor Barrier Effect (VBE).

The Vapor Barrier Effect depends upon minimizing the evaporation of moisture, and it is specified as useful when you are cold.

I recall cold & wet feet are the ideal environment for Trench Foot. The military suggests wearing clean and dry socks as a precaution - - as if CLEAN and DRY socks are always available.

The point is, the Vapor Barrier Effect seems to maximize conditions which give rise to Trench Foot.

I’m mindful, in a few days, hikers will be in town - - whereas the infantry may be living in field conditions nonstop for months - - therefore, using the Vapor Barrier Effect may not be of sufficient duration to cause Trench Foot among hikers.

I’m ambivalent.


Q2:

Should Zip-Loc bags be used only during “extreme” emergency circumstances? I’m unsure what conditions would qualify as an “emergency,” let alone “extreme.”


Q3:

Some people suggest wearing a liner sock over your foot, then covered by a Zip-Lock bag, wearing a regular hiking sock as the outer layer (not counting the shoe).

I’m under the impression, the Vapor Barrier Effect works best when the moisture-evaporation-restricting layer is in direct contact with the skin. The Effect may in fact be non-existent if the Barrier isn’t touching.

Is the liner sock suggested to enhance comfort? It seems to me, the liner sock would abrade moisture-softened skin and further reduce walking ability.

Any and all ideas are welcome.

Vi


* Re using Zip-Loc bags for the Vapor Barrier Effect. Other relatively non-porous materials may also be used - - large balloons, latex/non-latex gloves, MYLAR plastic (space bag/blanket), plastic wrap, heavyweight-silk bandana, waterproofed nylon, etc.

An obervation / inquiry which may or may not be directly on topic.


Q1:

I have read suggestions to wear Zip-Loc bags* over the feet in cold and wet conditions - - this is usually recommended for people wearing hiking shoes with soft-uppers - - to take advantage of the Vapor Barrier Effect (VBE).

The Vapor Barrier Effect depends upon minimizing the evaporation of moisture, and it is specified as useful when you are cold.

I recall cold & wet feet are the ideal environment for Trench Foot. The military suggests wearing clean and dry socks as a precaution - - as if CLEAN and DRY socks are always available.

The point is, the Vapor Barrier Effect seems to maximize conditions which give rise to Trench Foot.

I’m mindful, in a few days, hikers will be in town - - whereas the infantry may be living in field conditions nonstop for months - - therefore, using the Vapor Barrier Effect may not be of sufficient duration to cause Trench Foot among hikers.

I’m ambivalent.

Q2:

Should Zip-Loc bags be used only during “extreme” emergency circumstances? I’m unsure what conditions would qualify as an “emergency,” let alone “extreme.”


Q3:

Some people suggest wearing a liner sock over your foot, then covered by a Zip-Lock bag, wearing a regular hiking sock as the outer layer (not counting the shoe).

I’m under the impression, the Vapor Barrier Effect works best when the moisture-evaporation-restricting layer is in direct contact with the skin. The Effect may in fact be non-existent if the Barrier isn’t touching.

Is the liner sock suggested to enhance comfort? It seems to me, the liner sock would abrade moisture-softened skin and further reduce walking ability.

Any and all ideas are welcome.

Vi

* Re using Zip-Loc bags for the Vapor Barrier Effect. Other relatively non-porous materials may also be used - - large balloons, latex/non-latex gloves, MYLAR plastic (space bag/blanket), plastic wrap, heavyweight-silk bandana, waterproofed nylon, etc.

My understanding of the use of the zip lock or any VBL is to keep your feet dry, therefore warm in cold conditions. And indeed many swear by the Vapor Barrier Liner especially in a sleeping bag. My concern is the lack of breathability, thereby causing your sweat to accumulate, getting your feet (or other body parts) wet, causing you to be chilled. Or: causing the condition you were trying to avoid.

Seems to me the cold would be the bigest concern, but extended time having wet feet can cause trench foot. Probably not really a big problem on the AT, but if it's a concern to you, have a pair of dry socks for in camp, take the time to dry your feet completely (bandanas work well here.) then put on the dry socks. A little foot powder (Gold Bond is popular) goes a long way. Clean feet are happy feet, some use rubbing alcohol, altho I wouldn't use it during cold weather.

Give them a try, just be aware of the hazzards. Frost bite / frozen feet can be a bad thing. Could ruin your hike, will at least ruin your day. And trust me, hypothermia SUCKS!!!! No matter the cause.

Doctari.

Doctari,

My hope, when submitting my post (#277), was that someone intimately familiar with the Vapor Barrier Effect would advise me which of my presumptions are in error and where my concerns aren’t warranted.

I had three general areas of concern: (1) How does the Vapor Barrier work? Hopefullly this would include a discussion of the theory and some specific demonstrable anecdotes. (2) What are the limits of the Vapor Barrier Effect? How long does it work, and what stops it from continuing to work? (3) If, as I understand it, immediate contact with the skin is the most efficacious, how are suggestions to place things between the skin and the barrier explainable? Extending this, is the Vapor Barrier Effect causing some of my feeling of warmth when all I’m doing (or at least all I think I’m doing) is using a wind shell? (I.e., the windshell isn’t in direct contact with my skin, a la VBE, but separated by one or more layers.)

I dislike being wet, especially in winter, Vapor Barrier notwithstanding. I would consider carrying some type of plastic for emergency use if the VBE proves to be effective. But, as I suggested, I equate wetness in winter with inviting hypothermia.

My recollection, which may be imperfect, is the Vapor Barrier stimulates the retention of your perspiration (i.e., inhibits its evaporation) and the skin is "fooled" into "thinking" no more perspiration is needed. Your body registers that it is warm - - or, is it actually warmer?

I read an extensive explanation why the Vapor Barrier Effect works, but I’m unsure how much “science” was involved. I’m not finding that or any other “hard” information, so I’m asking around.

My recollection, which may be imperfect, is the Vapor Barrier stimulates the retention of your perspiration (i.e., inhibits its evaporation) and the skin is "fooled" into "thinking" no more perspiration is needed. Your body registers that it is warm - - or, is it actually warmer?


This would be great if it were true, but it's not. Your body and skin cannot be fooled. Even with no activity, like when you are sleeping, your skin gives off water.

What BJ said!

I think, for it to really & truely work, and I STRONGLY ADVISE AGAINST DOING THIS, is to spray your feet (or other body part) with anti-persperant. I STRONGLY ADVISE AGAINST DOING THIS, as there is a reason for your assorted body parts to sweat, not only to cool the area, but sweat is also a way of: getting rid of wastes, regulating the body's chemestry, etc.

Sportsmans Guide www.sportsmansguide.com (& other outfitters) oft times have goretex (tye) socks, give them a try, they allow your feet to breath, while keeping out water.

Doctari.

I read through this thread a day or two ago. Very interesting. My daughter and I talked (on a dayhike yesterday) about the fact that the people who had had the problems were apparently fit and male. My daughter and I tend to be cold most of the time (!) and are very diligent about keeping ourselves warm, so we've never been incapacitated by the cold. We made a few snide observations to each other about the bullheadedness of males, as well as envious comments about how nice it must be to be throwing off heat most of the time, as so many guys seem to do.

Moving forward to today. Daughter and I are getting ready to go for a dayhike, along with my 19-year-old son. It's raining and in the 40s. What does son choose to wear? Cotton boxers, cotton shorts, and a cotton T-shirt. Oh, yes, and cotton socks under his running shoes. We discuss. I mention that "cotton kills."

He responds, "You made that up! No one says that!"

We discuss some more, and finally set off in the car with him still wearing his all-cotton outfit and an old NF shell, but bringing a change of clothing in the car so he won't be sitting on the seat in wet shorts on the way home.

We set off on a three-hour hike, which is the first half of a planned two-loop circuit. Son's shell soaks through. His clothes get drenched. He's freezing, teeth chattering, but still will not put on a hat, a fleece, or anything else that his sister and I have in our packs. He wants to bail after the first loop. I take pity on him and agree to cut the hike short. Daughter and I hammer him with "I told you so's."

His defense for not listening: "I'm nineteen!"

I guess what I'm wondering is, is there anything short of personal experience that can make a believer out of someone?

His defense for not listening: "I'm nineteen!"

I guess what I'm wondering is, is there anything short of personal experience that can make a believer out of someone?

Not for nineteen year old males. You can only pray he lives through it.

Another way to deal with it - let him sit in the car and decide when to change into dry clothes. Enjoy the second loop with your daughter and laugh all of the way home.

Another way to deal with it - let him sit in the car and decide when to change into dry clothes. Enjoy the second loop with your daughter and laugh all of the way home.

LOL. Unfortunately, my daughter allowed as how she was ready to pack it in after one loop, too. We reminisced a lot about how much it was like hiking in Scotland--Scotland in the summer, that is.

Not for nineteen year old males. You can only pray he lives through it.

My ninteen year old male son turns 20 in less than 30 days, I pray he lives that long :datz
Fortunatly, he has had a few "life experiences" that have taught him that his mother & I sometimes actually know what we are talking about, and he actually listens (1 out of about 5 times, which is an improvement over 1 in 100) so I suppose there is hope. And, after all, I survived being 19 a Looooong time ago :D


Doctari.

My ninteen year old male son turns 20 in less than 30 days, I pray he lives that long :datz

Doctari.

Unfortunately, I don't think 20-year-olds are exactly in the clear either, though every passing year helps.

My 19-year-old hasn't actually been tooooo bad. (I hope I haven't jinxed us by saying that.) His older brother had a much more serious hypothermia incident when he was 15, as well as a very nasty broken collar bone, before he settled down a bit. Baby's car wreck last summer was kind of a nuisance...fortunately it was no more than that.

Per Marta, “We made a few snide observations to each other about the bullheadedness of males ... Son's shell soaks through. His clothes get drenched. He's freezing, teeth chattering, but still will not put on a hat, a fleece, or anything else that (we) have in our packs. ... I'm wondering ... is there anything short of personal experience that can make a believer out of someone?”


Some boys learn by watching; other boys just gotta pee on the electric fence.

Great info. Thanks, Old Farht. I have heard that when one is thirsty, one is already dehydrated, but did not know one was behind as much as a quart. It is easy to be become dehydrated in cold weather.

The theory of vapor barrier: http://www.warmlite.com/vb.htm

Rambler,

Thank you for the link. It provides some very interesting ideas.


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</td></tr></tbody> </table> "The theory of vapor barrier: http://www.warmlite.com/vb.htm" (http://www.warmlite.com/vb.htm)
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One of the things I've always laughed at are these folks selling items made of Killer Cotton, yet describe them as "Thermal Underwear", "Hunting Jackets" or "Outing shirts" etc, I guess its OK if you know its not going to rain and you're not going to sweat, or the temp stays in the 80's or above.

.........................I guess what I'm wondering is, is there anything short of personal experience that can make a believer out of someone?


NO, not unless his friends tell him the same thing you've been trying to. He'll listen to them. This has been my experience with teens/"young adults" anyway.

I have learned alot from the posts here in this thread, and will just say being from ohio i thought i was pretty well comfortable with cold weather but i had not hiked in really cold weather overnight actually. So my first trip i did not fully understand how important it is to Take off the sweaty shirt i had on all day. i did have a cool max shirt which wicks well but it did have the moisture feeling when i went to get in my sleeping bag. I felt chilly all night.I had put on my thermal poly shirt and down vest inside my sleeping bag. I finally ended up adding my jacket as well. The temp was well below freezing as my water bottle froze pretty solid by morning. I made it through the night but decided to go back and skip the rest of the hike.
I hope those people like me who are learning as they go find out as much as possible about hypothermia be fore they get to 5000 ft.

It's raining and in the 40s. What does son choose to wear? Cotton boxers, cotton shorts, and a cotton T-shirt. Oh, yes, and cotton socks under his running shoes. We discuss. I mention that "cotton kills."

My daughter would have worn flip flops.

I spend a lot of time in the summer months hiking in the White Mountains and i have witnessed various stages of hypothermia( even in July and August). The weather can and will change in an instant.. so be prepared when you get there during your through hike.

I always carry several packages of jello with me. When the person is diagnosed start them on warm jello water. Have them continue drinking until the need to pee. This has worked on 3 different people and it is a very simple fix, plus it is a great pick me up if you find yourself wet and chilly.

I spend a lot of time in the summer months hiking in the White Mountains and i have witnessed various stages of hypothermia( even in July and August). The weather can and will change in an instant.. so be prepared when you get there during your through hike.

I always carry several packages of jello with me. When the person is diagnosed start them on warm jello water. Have them continue drinking until the need to pee. This has worked on 3 different people and it is a very simple fix, plus it is a great pick me up if you find yourself wet and chilly.

WOW! Great Idea, energy and heat. Should work well, in conjunction with external warming, then followed by rest & (in my case) real food.

Any body ever consider using wet suits like divers use? They are very affective at holding in body heat and are very light weight. I dont how well they allow water to escape however (perspiration for instance)
A full body suit would be redundant for sure but what about just the vest?