How do warm blooded people cope

lachat

Member
Mar 6, 2024
16
5
Europe
I used my bivy and a tarp in the woods by a main UK airport sleeping bag. Ski jacket and fully clothed. I was not cold but, felt damp.

I found a perfect spot in the Spanish pyrenees. But, during the day it was sunny but, the air was very, very cold at night its exremely cold far too cold. I had a 20 year old min 10 rated bag. I was clothed and still cold.

I do struggle with cold weather a lot due to my herritige and living in an apartment which is often above 40° inside. I love it and have no issues.

How do you warm blooded people cope. I have heated clothing, sailing thermals, hot water bottle anything elce I should consider.
 
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Toddy

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Jan 21, 2005
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Some warm food inside you, and run about a bit, or do some really thorough stretching exercises before you go to bed.
I find that if I'm warmed up before I get into my sleeping bag, then I can sleep. It doesn't work for me to get into it cold and hope I'll warm up.
I find the hot water bottle helps too....and wearing a fleece hat. I feel the cold these days.
 
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Van-Wild

Full Member
Feb 17, 2018
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Here's some bro-science, that works for me......

Eat a meal that's higher in fat a few hours before bed. Infact, have a higher in animal fat diet as a general rule. Settles your metabolism and this relates to being able to regulate your body temperature.

Living in a house/apartment that is artificially heated to 40+ all the time may simply mean you're no longer acclimatised to the outside world, which in the temperate environment is a lot cooler! Try living in a cooler apartment. The added advantage of having cheaper living costs as well!

Your 20 year old sleeping bag may not be as efficient as it once was. I'd look into that if I were you. Any sleeping bag efficiency is improved by preheating it and allowing it to loft for a while before you get into it. Lay it out a good half hour before bed. Give it a good shake to puff it up and don't lay on top of it before you get in it or you'll just compress the fibres and the bag won't retain heat anywhere near as well. Exercise or at least move about a bit before bed. It generates internal heat. As the bag lofts, chuck in one or two disposable heat pads. They're very good. (If your hot water bottle isn't wrapped in an absorbant material, moisture will condensate on the outside of the water bottle and wet your sleeping bag. Think about that.

Wearing a massive ski jacket inside the bag isn't as effective as you think. You're crushing a lot of the jacket by laying on it, and the dampness you have inside the bag in the morning is due to the air not being able to circulate inside the bag and being trapped. This is because you're wearing too many big layers inside the bag.

Feet head and hands are all like little radiators. You lose so much heat from them. Consider wearing light gloves, good thick dry socks and wool Beanie or full balaclava when you go to bed.
 

Lean'n'mean

Settler
Nov 18, 2020
745
464
France
I have more trouble dealing with heat than with cold but there is one rule of thumb, if you're going to somewhere challenging, such as a mountain range, you need the correct equipement, clothing & sleeping system. A clapped out sleeping bag & a bivvy isn't going to cut it.
There are 2 lines of thought regarding sleeping bags, fully dressed or scantily dressed/nude. The idea behind sleeping bags is that one's body heat warms the air inside the bag & the insulation prevents a lot of that heat from escaping but if one is fully or heavily clothed, then the sleeper ends up lying in cold air, as the clothes prevent the body from heating the air inside. This is entirely up to the individual of course but I have learnt the best method for me by being pretty cold & miserable on occasion in my younger years.
 
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Herman30

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Aug 30, 2015
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..living in an apartment which is often above 40° inside.
Is that Celsius or Fahrenheit?

If Celsius it is no wonder that you can´t stand cold. I would die if my appartmen was so hot, +20 C is about right for me. We don´t even get +40 ever. Hottest summer it can get to +30 outside for a short period. But that is unusual.
 
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TLM

Bushcrafter (boy, I've got a lot to say!)
Nov 16, 2019
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Vantaa, Finland
if one is fully or heavily clothed, then the sleeper ends up lying in cold air, as the clothes prevent the body from heating the air inside.
Even sleeping bags have to follow physics and that idea is not supported by it. The heat that escapes through your clothing has to go somewhere and where it goes is to the air inside your bag. Yes that air is cooler than with less clothing but the clothing you have on causes the difference.

If one takes that idea to the logical conclusion if one dresses like a Michelin man one freezes to death almost instantly when going inside the bag. So far that has not been observed.

One also has to manage the moisture one sweats out, often people who complain about cold have sweated their clothes and bag insulation moist.
 

Broch

Life Member
Jan 18, 2009
8,492
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www.mont-hmg.co.uk
Even sleeping bags have to follow physics and that idea is not supported by it. The heat that escapes through your clothing has to go somewhere and where it goes is to the air inside your bag. Yes that air is cooler than with less clothing but the clothing you have on causes the difference.

If one takes that idea to the logical conclusion if one dresses like a Michelin man one freezes to death almost instantly when going inside the bag. So far that has not been observed.

One also has to manage the moisture one sweats out, often people who complain about cold have sweated their clothes and bag insulation moist.

I have given up trying to explain heat transfer physics to people :)
 
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Pattree

Full Member
Jul 19, 2023
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Just think if a cool box (esky).
If you put something cold inside it it stays cold.
If you put something warm inside it it cools much slower.
If you put a well fuelled heat generator (@36 deg C) in it, you give whatever insulation it has the best chance to operate.

The rating system presumes that you will be wearing a base layer. That’s what I sleep in.

Edited to add:

Heat can’t move from a cooler to a hotter.
You can try it if you like but you’d far better notter.


Flanders and Swan
The laws of thermodynamics.
 
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jeggs

Member
Oct 9, 2023
20
16
46
london/devon
Here's some bro-science, that works for me......

Eat a meal that's higher in fat a few hours before bed. Infact, have a higher in animal fat diet as a general rule. Settles your metabolism and this relates to being able to regulate your body temperature.

Living in a house/apartment that is artificially heated to 40+ all the time may simply mean you're no longer acclimatised to the outside world, which in the temperate environment is a lot cooler! Try living in a cooler apartment. The added advantage of having cheaper living costs as well!

Your 20 year old sleeping bag may not be as efficient as it once was. I'd look into that if I were you. Any sleeping bag efficiency is improved by preheating it and allowing it to loft for a while before you get into it. Lay it out a good half hour before bed. Give it a good shake to puff it up and don't lay on top of it before you get in it or you'll just compress the fibres and the bag won't retain heat anywhere near as well. Exercise or at least move about a bit before bed. It generates internal heat. As the bag lofts, chuck in one or two disposable heat pads. They're very good. (If your hot water bottle isn't wrapped in an absorbant material, moisture will condensate on the outside of the water bottle and wet your sleeping bag. Think about that.

Wearing a massive ski jacket inside the bag isn't as effective as you think. You're crushing a lot of the jacket by laying on it, and the dampness you have inside the bag in the morning is due to the air not being able to circulate inside the bag and being trapped. This is because you're wearing too many big layers inside the bag.

Feet head and hands are all like little radiators. You lose so much heat from them. Consider wearing light gloves, good thick dry socks and wool Beanie or full balaclava when you go to bed.
Hi VanWild
I must admit all round very good points you raised especially with the acclimated point and the layers issue inside the sleeping bag, being able to have suitable layers the wick and let the expelled water from our bodies dissipate is essential.

However there is one point I'd like to question. Your promotion of an animal based fat intake. I'm a vegan of 8 years and vegetarian prior to that for 24 years, I've never felt better (and a recent comprehensive medical verified this)..I would agree with you that a warm meal with a slightly higher fat/calorie content helps with warmth during the night. A teaspoon of olive oil contains around 100 calories and provides essential fatty supplements without the cholesterol rich animal fat. I personally don't think you ( not you personally-im using you as a general term for readers) need animal fats to achieve what your suggesting for warmth at night. Of course it's all done to individuals choice, much like bushcraft is, i.e. is a machete better than a small axe or bill hook...we all have our own preferences
 
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Pattree

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Jul 19, 2023
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@TLM
The full law states that Heat cannot OF ITSELF move from a cool body to a hotter body. A heat pump uses a LOT of electricity to power the process. The sleeping bag analogy might be a hot water bottle.

Theoretically you can’t let cold into your warm house but the whole world knows that you can if it’s (energetically) carried by cold air.
 
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TLM

Bushcrafter (boy, I've got a lot to say!)
Nov 16, 2019
3,257
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Vantaa, Finland
A heat pump uses a LOT of electricity to power the process.
Actually not a lot, with achievable COP 5 I would say it is not a bad trade, 3 is true even with the larger temp differences..

Read the last sentence.

While I am not a thermodynamicist I know the practical implications quite well having worked with heat conduction (and a bit with radiation) in satellites and having done more than my share of heat stress and strain calculations.
 

Paul_B

Bushcrafter through and through
Jul 14, 2008
6,413
1,702
Cumbria
When you're tucked up ready for sleep eat plain, unsalted peanuts. They're high in protein and fats, not necessarily bad ones, that your body uses as energy rich but slow burn fuel. As you're digesting them you gain from a very natural process called thermogenesis. This is where the digestion produces bodily heat. It will happen 20 to 30 minutes after eating. The benefit of this is a bit of extra warmth as you are falling asleep, which imho helps a lot. Then the fats will last a long time as fuel for the energy demand your body has to thermoregulate.

This is my pseudoscience view on keeping warm but it always worked for me.

While other fat rich foods exist imho peanuts of the plain, uncoated and unsalted variety is the most portable and easily digested food for this purpose. I use it as snack food when working from home. Just ignore the red dietary indicators as imho that just shows how inadequate the dietary traffic lights system really is.

One final point is kit. Make sure your sleeping bag fits. Too big you get a lot of voids to heat up, consider tying excess length off. Too tight on girth or length and you'll compress the infill reducing efficiency. This can also happen if you put a jacket over the top for extra warmth, this might actually reduce overall insulation. Or if you wear too much inside the sleeping bag and the down compresses inside out. Or if you wrap your quilt around you too tightly for that snuggly feeling.

The other thing to point out is body fat. I'm making no assumptions or comments on anyone but myself. Years ago when into whitewater kayaking I was lean and cold. I then put on weight and felt under the same conditions as the previous year I felt the cold slightly less. Then I lost weight and felt the cold again. For a couple of years I tested this by putting weight on for winter kayaking and taking it off again for summer hiking. It kind of helped but could just be in the mind.

These are my opinions and experiences only. They may not be real!
 

demented dale

Full Member
Dec 16, 2021
1,022
485
58
hell
I used my bivy and a tarp in the woods by a main UK airport sleeping bag. Ski jacket and fully clothed. I was not cold but, felt damp.

I found a perfect spot in the Spanish pyrenees. But, during the day it was sunny but, the air was very, very cold at night its exremely cold far too cold. I had a 20 year old min 10 rated bag. I was clothed and still cold.

I do struggle with cold weather a lot due to my herritige and living in an apartment which is often above 40° inside. I love it and have no issues.

How do you warm blooded people cope. I have heated clothing, sailing thermals, hot water bottle anything elce I should consider.
You didnt mention what was underneath you so I am guessing just the bivy bag. Most heat is lost into the ground and the exchange coming up feels damp. I dont know anything about gear but when I went hitchhiking in Europe and living outside. The old guys told me to sleep on cardboard and if it got really cold to put newspaper in my clothes. It worked a treat and I've always done it ever since.
ps I reckon that flat of yours is making you soft. Get out in the cold and man up :) x
 

bearbait

Full Member
Lots of good comments and suggestions above.

I sleep lightly clothed (just a merino base layer) in a silk liner in the sleeping bag. Other clothes, blankets, etc. - if felt necessary - on top of the bag to slow the heat loss from the bag. If the bag has no hood then a woolly hat is a good alternative.

Starting off the night in the bag with warm feet is also a great help, I find. I have a set of down bootees to this end, or thick socks as an alternative.

Not sleeping in one's day clothes is also a good idea in my view, as these will contain moisture from the day's activities.
 

Kadushu

If Carlsberg made grumpy people...
Jul 29, 2014
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No one's mentioned entropy yet or how the Higgs boson relates to all this
 
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