A lot of great advice on this thread already.

I'll just reiterate what I see as the highlights.

Definitely get enough r-rating in the pad. The bag isn't enough by itself. You WILL be cold in the warmest bag, if you don't get enough pad. Do at least as much research on warm pads as you do on your warm bag. There is plenty of search data in the archives on winter pad strategies and discussions on which ones are warmest and most comfortable.

Pick a bag that is rated at least 10-15 degrees lower temp than you expect to encounter. And pick it from a maker that is known to be pretty accurate with their ratings. Like Western Mountaineering.
Some makers will rate a bag for much colder temps than it can really work in. It's not uncommon at all. Again, the search is your friend here, and you can glean some info from the archives about which makers rate accurately and which makers don't.

Good light clothing that works as insulation can help a lot, as long as it is DRY.
I recommend full head-to-toe coverage, including a balaclava or even a down hood on the head.

Hot water bottle is great, as long as you have a bottle which you are sure will not leak. Even if it does cool off inside by morning, you'll at least had the majority of a good night's sleep. If it's really cold, and you have to get up to pee in the middle of the night anyway, you might heat up the water and put it back in the hot water bottle again.

And lastly, because most people do not want to bother themselves with a vapor barrier layer, look into vapor barrier layers. They work very well in cold weather, but they require some ability to monitor your heat level so you don't sweat. For you, I expect that would be a welcome "problem". So, look into it. It's a specialty system that most people don't want to bother with, but it does work, especially in the very cold.

Some good ideas here. I especially like the "puffy pants" suggestion- I might well try that one!

Several people have brought this up, and I'll just chime in- if you have an air mattress you might well benefit by using a layer of CCF on top to reduce conduction of the cold from the ground. Even an insulated air mattress can conduct cold. I used to just sleep on CCF but as I've gotten older I've found that's not something I want to do any more and I've gone to an insulated air mattress (12 oz) plus a 3/4 length z-rest. I might look into these 1/8 or 3/16 CC foam pads I keep hearing about on this forum but haven't yet found the vendor that sells those thin mats.

One thing that surprises me is how many people have stated that their hot water bottles are not warm in the morning. Mine stay warm all night long, and are still VERY warm to the touch in the morning. I boil the water, pour it in the bottle, drop the bottle in a sock and the sock keeps the bottle from burning me but also insulates the bottle. Even sleeping in snow shelters in the winter I've found that my bottles are still significantly warmer than body temperature in the morning.

But +1 for sure on taking care that your hot water bottle doesn't leak. I am very careful to tighten the cap and then place them cap side up in the bag. If I roll to my side, I re-position the bottle so that it remains cap side up. Just in case.

Some more input from another cold sleeper...

I just went through all this myself. I used to have an old Sierra Designs Rosa 20F synthetic bag. After putting on every layer I had, including my rain gear, and still being cold on a wet & cold Memorial Day car camping trip, I invested in a new sleeping bag. I specifically chose a women's bag with an EN comfort rating (not lower limit or survival rating) below that which I expect to sleep in. I picked the REI Joule bag (rated to 22F) since the weight and price were right (WM or Feathered Friends were on my list, but the REI bag was on sale and saved me about $200). I've been warm and cozy in it on the 3 trips I've taken since, though none have yet been as cold as Memorial Day. Instead of wearing all of my clothes in my bag, I've been comfortable (and even too warm) in just midweight wool long undies and socks. My suggestions for keeping warm pretty much echo everyone else's, but I'll list them anyway:

- Warm sleeping bag and pad. My pad is a Thermarest Women's Prolite 4 - heavy but warm and cushy.
- Have a warm drink before bed - hydrates as well as warms, and staying hydrated is a key to staying warm. I'll usually have something to eat before bed as well.
- Wash and change before bed - I read somewhere that removing sweat/salt from your skin helps you to regulate body temperature better... I don't know how effective it is, but I have a wash off and change into my sleeping clothes before it gets cold if I'm just sitting around camp.
- Down booties - mine are Sierra Designs and weigh about 3oz... I've been so warm in my new bag that I've been kicking them off in the night though!
- Hot water bottle between the legs - this is much more effective than between the feet.
- Wear a hat or balaclava to bed if it's really chilly.
- Do some jumping jacks before retiring for the night... not enough to make you sweaty, but just a few to get the blood flowing.
- Get a dog! You might have to tech it how to share, but snuggling up with my coonhound helps keep us both warm. Major disadvantage - she snores like an express train and never apologises for farting in the tent :\

When I hike I overheat, when I stop walking I freeze; it's like my pilot light goes out. What to do about it? I have an underactive thyroid.

I'm a cold sleeper. What works for me. I wear fleece socks inside my down socks.
It doubles the heat.
I use a cuben quilt, heats up instantly but you can't wear down clothes inside it since it's a vapor barrier.

Around the campfire I put on down pants.

Wood stove inside of a tent? Might be a good option if you ever camp in the snow.

Thanks, Tom, I forgot about vapor barriers! I find a vapor barrier really useful on below-freezing nights to keep body moisture from getting into my sleeping bag. That's one reason I have non-breathable rain gear (the other being that I get just as wet inside expensive "breathable" gear which wets through a lot sooner than coated nylon). Just remember that anything inside the vapor barrier will be damp, so don't wear your down inside. I wear my vapor barrier over my base layer, with my insulating items outside the vapor barrier.

My dog certainly helps, too--I consider him part of my sleep system. There have been a few nights when I would have liked to have three of them! The main precaution is to keep the dog's claws well-trimmed and keeping him off your air pad and lightweight-shelled down sleeping bag. And, of course, lots of obedience training courses for you and your dog before you take him out on the trail.

Edited by hikinggranny on 08/24/2012 01:05:58 MDT.

plenty was written about optimizing the heat retention, bed bottle, clothes.

But what about boosting the heat source?

Let's examine why two people, 1 man vs 1 woman, same age, height, body weight and similar BMI have different thermal requirements.

I understand that I may trigger some battle of the sexes hate flames, but I didn't design the human body, so don't blame me.

Check with your doctor to validate your own stats.

Men generally have a high protein and high iron diet.
Women generally have a low protein, high carbs and sugar diet.
Women also regularly loose some iron on the 28 cycle.

Do you guys hate and want me to shut up yet? ok I'll continue anyway.

Since you are aware that your body generates the heat source, let's examine why?
The human body is like a furnace or fireplace. You toss a fuel source and it will burn to generate heat. but to retain heat, a furnace and fireplace have iron, insulation and bricks, that continue to store and radiate heat.

People that have a higher than avg body fat % (women?) get cold faster. Fat is a fuel source, but it is a lousy insulation and retainer of heat.

People that have a higher than avg iron % (men?) are always heating up. Iron is the body's insulation, like a Thermos or the inside of a kitchen oven.

My wife - same problem. surprised? no.
Her Dr ran a blood test and put her on a vitamin regiment. you can look up all the dark green leaves spinach and low-fat meat protein (filet mignon/salmon) foods.

problem is not fully solved, but she is comfortable wearing shorts in 72F weather, whereas before, she was freezing in the July/Aug heat wave under a down comforter wearing layers of PJs.

It's not a quick solution or shortcut like all the previous posts. We're talking about changing your food intake for about 9 months before your blood test results will improve.

Look up the Red Cross blood donation centers, they have a list of recommended high iron foods. Most Americans do not like the flavor, but beef liver is very high on iron.
Again - check with your doctor, because beef liver is also super high in bad cholesterol.

but on the healthy side - filet mignon is lean in fat, high iron and protein, spinach and broccoli are a good iron source if you make them part of your daily meals.

Edited by RogerDodger on 08/24/2012 20:01:29 MDT.

Rodger, who told you this stuff or where did you read it? It's not jiving with what I have learned in biology/physiology/nutrition classes and what I and am reading. Here's some research based info...

"Women also regularly lose some iron on the 28 cycle."
An old study came to the conclusion that "There was no decrease in the incidence of iron deficiency following the menopause" (http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2141.1967.tb08846.x/abstract) Sooo, this does happen, but not really statistically common. More period information, yay. Anyone hating me for this too?

"People that have a higher than avg body fat % (women?) get cold faster. Fat is a fuel source, but it is a lousy insulation and retainer of heat."
Look at this scientific study that says the exact opposite: http://www.ncbi.nlm.nih.gov/pubmed/2803162

"People that have a higher than avg iron % (men?) are always heating up. Iron is the body's insulation, like a Thermos or the inside of a kitchen oven."
I've been googling this for the past 15 minutes and I'm coming up with nothing to support that iron insulates people. Nothing to oppose it either, just nothing at all about the insulative properties of iron in people.

Edited by heathert on 08/26/2012 23:44:21 MDT.

Heather,

My info is not my opinion - it's derived from women in my circle of friends and family, and the doctors feedback that was given to them. I am not a doctor, so the info I share is accurate by a third degree of separation from the doctors and lab technicians.

Since this topic comes up quite a lot in my circle, my experience has been that the info, advice and remedy are consistent. Everyone's body, diet and regional climate are different, that is why I say to start with a doctor visit, and have a review of the blood test results.

For people that have donated blood to the Red Cross, there is a test that is done prior to the donation. They prïck your finger tip, for a blood sample, and drop it in a blue green iron solution. If your blood sample sinks then your iron level is OK, if the drop of blood struggles to sink, then your body's iron level is too low to donate.

I have no interest in a pointless battle of the sexes debate.
I share the info as advice. Take it, or leave it. No gain or loss for me.
Do what works for you.

We're in the So Cal region.

I was undecided to share this other info, because it might take the thread in another tangent. A person in my circle with C-word, going through chemo, has a major deficiency in red blood cells, he (not she) is freezing in 90F-100F weather, and wears an arctic down coat all the time. The C treatment center doctors recommended he eat a lot of lean, low fat, red meat for most meals to boost the red blood cell and iron stats.

Edited by RogerDodger on 08/27/2012 09:42:52 MDT.

Roger-

FWIW, my experience doesn't jive with your posts at all. I eat exactly the same food (high protein, high (good) fats, low carbs) as my husband. He's a furnace, and I'm cold. I've never tested low on iron, and have been tested multiple times. I do test low on vitamin D if I don't supplement but that has a lot to do with living in Alaska (not enough UV radiation to trigger the natural production of vitamin D 9 months out of the year). I supplement with D daily in the winter months, a couple times a week in the summer, and get my bloodwork done twice a year.

The only food I've found that seems to impact my body temperature is actually a spice- cayenne. I have experimented with some success on drinking a tea with a good dash of cayenne before bed and have found that it helps me to feel warm for quite a while after consumption, in the same way a spicy soup or chile might make you sweat when eating it.

Edited by EagleRiverDee on 08/27/2012 11:53:15 MDT.

Dena Kelley,

It's a combination of at least two things:
1) You need fuel to burn - to generate heat
2) You need to maintain, insulate, and radiate heat.

That is why many suggest eating high caloric meals before bedtime. digesting and breaking down foods in the stomach generates heat. Gross to compare a human body, but similar to an organic compost pile that runs hotter than the ambient temperature.

Also someone suggested a quick form of no-sweat exercise such as 10 push ups or jumping jacks. People facing hypothermia have said that clapping their hands sends blood cells rushing to the hands. Exercise is another way of asking the body to convert and burn body fat fuel into energy for movement - byproduct is heat generation.

Dena - you stated you are in Alaska, but the original poster has a locale of New Mexico, that is why I approximated to be closer climate to Southern Calif.


I found a website that may be of interest
http://antranik.org/regulation-of-body-temperature/
I did not consider that exhaling is also a likely source for heat loss, interesting.


A less scientific article:
http://www.cbsnews.com/2100-500165_162-7328948.html
"...Probably the most common for women are anemia or a low blood count or an underactive or low-fuctioning thyroid."

Edited by RogerDodger on 08/27/2012 14:17:43 MDT.

The FF Spoonbill double bag seems like just the ticket. I thought it looked great, but just to warm for our normal temps, but if you are looking for a warm 20F bag, it seems like it would be the ticket, with it's independent hood/zipper adjusting lettting your sleeping partner air out while you bundle up. Then increase the delta by wearing warm down clothing.

Whether or not iron is an "insulator" I cannot say; however, spinach as a good source of iron is an old wives tale. Yes, it has a high content of iron, but it also has a high content of oxalic acid, which inhibits the body's uptake of the iron. By comparison, the little oysters in a tin of smoked oysters (ummm good!) contain 35% iron...much tastier than liver, and they go quite well with cheese and wine. Happy Trails!

My 92 year old grandma just told me that when she was in girlscouts she put in heated rocks/bricks in her sleeping bag

"Fat is a fuel source, but it is a lousy insulation and retainer of heat. . . Iron is the body's insulation, like a Thermos or the inside of a kitchen oven."

My MD/PE household responds:

Fat on the human body is very much an insulator against conductive heat loss. We've butchered arctic critters including a bowhead whale and the mostly furless ones have their fat concentrated under the skin where it does the most good. A human's coolest skin (given the same exposure) are those areas over the most white adipose fat. (The brown fat in the small of the back is an exception - it is involved in metabolism in both genders).

Iron is used in hemoglobin in our blood to transport oxygen to our cells and carbon dioxide back to our lungs. It is not insulation.

Editted for spelling.

Edited by DavidinKenai on 09/05/2012 16:58:04 MDT.

Thanks David. That was the first time I had heard the claim that fat was a " lousy insulator".

ideally someone (Mythbusters, are you listening?) will do this experiment.

at 10PM, a cold camper will cuddle up to 20 lbs of pork lard in a zip lock bag, preheated to Human body temp 98.6F, and another will do the same with 20 lbs of soft iron pellets in a bag, preheated to the same temp.

wait 4 hours, and revisit at 2AM, when campsite ambient temperatures dip.

Which object do you think will retain the heat source the longest, a sac of fat or a sac of metal.

PS: this isn't the same as a pound of feathers vs a pound of lead, which is heavier - riddle.

Also, to be sure we are using the same meaning, I'm going with this definition, until someone provides a better dictionary.

Insulate: to cover, line, or separate with a material that prevents or reduces the passage, transfer, or leakage of heat

Edited by RogerDodger on 09/05/2012 17:04:43 MDT.

Sounds more like a test of thermal storage, rather than insulation.

thermal storage AND insulation.



again with my Thermos analogy.
its made out of glass and webbed metal wires.

if it keeps hot liquid contents hot and cold liquid contents cold. then its insulation.

the material itself being that same temp, is thermal storage.

but it functions as both, not one without the other.

Edited by RogerDodger on 09/05/2012 17:29:47 MDT.

thoughts from yet another one who could've posted the title:

For me, double quilt or sleeping bags zipped together don't work well - because whenever my partner rolls over or gets up to pee (which happens several times a night) I get a blast of cold air that wakes me up. Your experience may not be the same; this is just a cautionary thing you may want to consider. For me, direct access to the heat source is outweighed by the random ventilation occurrences!

My feet are usually a bit chilly by the time I climb in the bag (heck, they're chilly right now in my 70 degree house!), so a hot water bottle by the feet is the best placement for me.

I definitely recommend using a pad long enough to have it extend under your feet, with high enough insulation value (women's neo-air xlite has worked for me so far but I haven't had it in really cold conditions yet; perhaps the xtherm for you?)

I've just changed from an old REI Down Time bag to a WM Versalite 10 degree bag - love it. Have also made myself a sleep hat from heavy windpro fleece.