Feeling clammy when sleeping in cold weather

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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Sun 22 Jul, 2018 1:52 am

Orion wrote:
So you're going to double down on this?


On what - reality?

It's all there in black and white, champ.

Orion wrote:
I didn't misquote you. You stated something that is physically impossible, not something that "usually" doesn't happen. You'd need to rejigger the laws of thermodynamics if you want a hotter body to emit less energy than a colder one.



jdeks wrote:Increase the insulation even more, and you can potentially hold so much heat that the bag skin will then warm, even with the consequent increase in radiant heat loss. In this case,you will indeed be losing more heat energy, but youd want to be - or you'd probably overheat.


Second time I've had to repeat myself, and spit out the words you're trying to put in my mouth. Quit trying to turn this thread into a p155ing contest
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Re: Feeling clammy when sleeping in cold weather

Postby Orion » Sun 22 Jul, 2018 2:52 am

jdeks wrote:
Orion wrote:
So you're going to double down on this?


On what - reality?

It's all there in black and white, champ.

Orion wrote:
I didn't misquote you. You stated something that is physically impossible, not something that "usually" doesn't happen. You'd need to rejigger the laws of thermodynamics if you want a hotter body to emit less energy than a colder one.



jdeks wrote:Increase the insulation even more, and you can potentially hold so much heat that the bag skin will then warm, even with the consequent increase in radiant heat loss. In this case,you will indeed be losing more heat energy, but youd want to be - or you'd probably overheat.


Second time I've had to repeat myself, and spit out the words you're trying to put in my mouth. Quit trying to turn this thread into a p155ing contest


So a really warm bag will result in faster heat loss?

The only reason I brought this up is because it was part of your diagnosis of Huntsman's problem. You said that the presence of moisture on the shell could be a sign that it wasn't a warm enough bag. I was hoping you'd clarify that but instead you took a position at odds with basic physics. Most of what you're posting seems on the mark to me but this one stance is quite odd. I'm not sure why you are so keen to hold onto it.
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Re: Feeling clammy when sleeping in cold weather

Postby Warin » Sun 22 Jul, 2018 8:06 am

Orion wrote:
jdeks wrote:Okay I'm goinna lay this out in a bit more detail. Whether folk read it is up to then, but dont come back at me unless you get to the bottom.

Heat energy creeps from the body outwards through the insulation, warming it as it goes. The speed of this is pushed by temperature difference, at first between the warm body and the inner skin of the bag, then between the warming inner skin and the first 'layer' of down, then between this layer and the next, and so on, right up to the outer skin.


So you're going to double down on this?

I didn't misquote you. You stated something that is physically impossible, not something that "usually" doesn't happen. You'd need to rejigger the laws of thermodynamics if you want a hotter body to emit less energy than a colder one. I thought you'd recognize that but instead you came back with a painfully long hand waving attempt to explain it all away. It was hard to read all that as it just dug the hole deeper.


'Speed', 'time' etc are just thermal mass and for simplification to a steady state can be ignored.

The system can be simplified ... and modelled as one thermal path from the bags outer to one heat sink. At that point the argument falls down. No amount of argument by trying to make the model on the inside of the sleeping bag more complex changes the outside model.

The statement stands that an increase in the bags insulation will lead to an in the bags skin temperature is correct.

---------------------------------------
However, I think, jdeks argument is about the moisture/humidity in the bags insulation...
While dry a bag may have more insulation, but when damp it can have effectively less insulation than a bag that has less dampness and less insulation.

The problem then becomes one of determining that amount of that moisture and its effect on the insulation. Down will suffer more insinuation loss from moisture compared to artificial insulation. And using an artificial insulation may go some way to solving that issue.
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Re: Feeling clammy when sleeping in cold weather

Postby neilmny » Sun 22 Jul, 2018 8:10 am

Hi Huntsman,

My mat is an Exped Synmat UL 9. This is a review I found http://backcountryskiingcanada.com/Expe ... L-9-Review
The specs -
Weight: 795g / 1.75lb
Dimensions: 197× 65cm / 78 × 26"
Packed Size: 27 × 13cm / 10 × 5"
Thickness: 9cm / 3.5"
R-value: 6.0
Colour: Yellow
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Re: Feeling clammy when sleeping in cold weather

Postby Franco » Sun 22 Jul, 2018 8:28 am

Do you use 2 mats? Haven't seen a mat above R4.4...

The Therm A Rest XTherm is rated at 5.7
The Exped Downmat UL Winter M is rated R7.
There are others but those two are a bit lighter.
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Sun 22 Jul, 2018 9:47 am

Orion wrote:So a really warm bag will result in faster heat loss?


No...

jdeks wrote:Takehome message here is that it's an interlinked multivariable system. It's not just "more x = more y".


You're oversimplifying.

When you say 'really warm bag', do you mean a bag with more insulation? A high internal temp? Or a high insulation temp? Or a combination of these? All affect each other, and the outcome.

With the right balance, more insulation can bring up the core temp, insulation temp, and thus shell temp. Yes, this also means you reach an equilibrium with a (slightly) greater overall rate of thermal loss - this is what you WANT when your bag starts to get too hot. I know it's counter-intuitive, but its observable. This is why you can have (quality) 3-season bags that work from +10C to -5C - they moderate themselves based on their own temperature.

It's worth noting that with a (mostly) fixed interior temp of 38C, this 'self-heating' phenomenon tends to be limited to mild conditions. Once it gets properly cold, the greater overall thermal drive and thicker insulation depth means getting a heat soak though the full insulation thickness isnt really feasible.

The reason I'm "so keen to hang on to this" is there's so much speculative pseudoscience and misinformation that comes forth on these discussions ("condensation descends from the sky", "peeing out heat energy helps you stay warm") that the poor questioner winds up just perpetuating the same common misconceptions and usually winds up disappointed anyway. I'm still waiting for someone to suggest a bivvy bag.... :roll:

More than a new sleeping bag, the OP is served better by know WHY they're having the problems they are.
Last edited by jdeks on Sun 22 Jul, 2018 9:59 am, edited 1 time in total.
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Sun 22 Jul, 2018 9:54 am

Warin wrote:
The system can be simplified ... and modelled as one thermal path from the bags outer to one heat sink. At that point the argument falls down. No amount of argument by trying to make the model on the inside of the sleeping bag more complex changes the outside model.

The statement stands that an increase in the bags insulation will lead to an in the bags skin temperature is correct.



Well, sorry, but no, that's not the statement I made, at least not in full. It can, sometimes, but depends on multiple factors. See above.

The system really can't be simplified, least not as youre saying. The variables al affect each other. We haven't even touched on the body's own nature to vary heat output, or boundary layers of warm air forming around the bag, due to shell radiation.

Warin wrote:
However, I think, jdeks argument is about the moisture/humidity in the bags insulation...



Yes and no - moisture and humidity play a part but they're not some isolated factor. They're just as much an ever-present variable of the system as a whole, and it needs to be understood as a whole to find whether they're the real issue.
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Re: Feeling clammy when sleeping in cold weather

Postby Warin » Sun 22 Jul, 2018 10:39 am

Huntsman247 wrote:
Warin wrote:
Neo wrote:Full bladder, better to get up and pee as the body puts it's heat to the bladder and extremities get cold.


Better to pee into a bottle .. and then use the bottle as a hot water bottle untill it cools.
This way you relieve the bladder, don't waste heat getting out of the bag cooling your body, bag and tent, and make use of the heat in your pee.


As long as you don't recycle it further I won't judge :wink:


You did ask :roll: ?
Read 'Skeletons in the Zahara' (note the Z rather than an S) for a comparison of the taste and usefulness of human, camel and horse pee. An interesting read.
Tells the story of an American ship wreck on the Moroccan coast ~1815.
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Re: Feeling clammy when sleeping in cold weather

Postby Huntsman247 » Sun 22 Jul, 2018 3:04 pm

jdeks wrote:You're not getting 'sweaty' because you're cold. You're constantly perspiring and emitting water vapor, you're in a cold alpine environment with high relative humidity, and your bag is too cold to keep your sleep zone warm enough to keep your perspiration as vapor. Bags, jackets and everything else is only breathable if the water is evaporated. When the whole bag, and well as you and your pants, are under dew point, that goes out the tent door.. Hence it's gathering as 'clammy' condensate on you and the inside of your bag.

Go try it somewhere REAL cold like Majura, and you'll get to wake up with the wonderful experience of having your own clothes frozen to the inside of your bag., while you're still wearing them.


Cinching the bag closed, in this case, isn't the main problem. It's just not helping, and if anything, hindering moisture evacuation. As neilmny's story illustrated, if you're warm enough but the rel humidity is high enough to make your feet sticky, a bit of air circulation fixes it.

Other angle is just get warmer, so the moisture evaporates effectively. In which case, cinch away!



It's made sense now! Thanks for the long explanation too jdeks I understand the problem much better now.
As for Majura, It sounds like a fun experience! lol. Would be cool to experience that once I guess.

Thanks Orion and jdeks. I've pieced a good picture of my problem and understand why from your 'discussion'. So thanks and it's been entertaining. :wink: I did a bit of google before posting the question initially and pretty much this thread seems to offer the most logical answer. :roll: what some people come up with and expect you to beleive...

neilmny wrote:My mat is an Exped Synmat UL 9. This is a review I found http://backcountryskiingcanada.com/Expe ... L-9-Review
The specs -
Weight: 795g / 1.75lb
Dimensions: 197× 65cm / 78 × 26"
Packed Size: 27 × 13cm / 10 × 5"
Thickness: 9cm / 3.5"
R-value: 6.0
Colour: Yellow


Interesting mat. Bit on the heavy side though... But I guess that's a pretty high thermal rating.

Franco wrote:The Therm A Rest XTherm is rated at 5.7
The Exped Downmat UL Winter M is rated R7.
There are others but those two are a bit lighter.


I stand corrected. Good to know. Will take a look into them and see if I can tempt myself but I used to use the Klymit inertia x frame for winter. So having the R4.4 rating is already a luxury for me. Probably won't unless I plan a trip that requires snowshoes. Thanks though.

Warin wrote:
Huntsman247 wrote:
Warin wrote:
Better to pee into a bottle .. and then use the bottle as a hot water bottle untill it cools.
This way you relieve the bladder, don't waste heat getting out of the bag cooling your body, bag and tent, and make use of the heat in your pee.


As long as you don't recycle it further I won't judge :wink:


You did ask :roll: ?
Read 'Skeletons in the Zahara' (note the Z rather than an S) for a comparison of the taste and usefulness of human, camel and horse pee. An interesting read.
Tells the story of an American ship wreck on the Moroccan coast ~1815.


*facepalm* lol sounds like an interesting book.
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Re: Feeling clammy when sleeping in cold weather

Postby north-north-west » Sun 22 Jul, 2018 3:32 pm

Thanks to the physics geeks from here too.

And thanks to Huntsman for raising this one. It happens to me sometimes when I sleep in the car and I've always assumed it was due to sweat from overheating, even though I've felt chilled. It's great to finally understand what's going on.
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Re: Feeling clammy when sleeping in cold weather

Postby neilmny » Sun 22 Jul, 2018 3:58 pm

north-north-west wrote:Thanks to the physics geeks from here too.

And thanks to Huntsman for raising this one. It happens to me sometimes when I sleep in the car and I've always assumed it was due to sweat from overheating, even though I've felt chilled. It's great to finally understand what's going on.


Holy crap can someone explain in dumarse terms what all this means.....we cretins need to understand too.
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Re: Feeling clammy when sleeping in cold weather

Postby Warin » Sun 22 Jul, 2018 4:12 pm

neilmny wrote:
north-north-west wrote:Holy crap can someone explain in dumarse terms what all this means.....we cretins need to understand too.


First Rule: Keep your sleeping bag dry. That includes your sweat when you sleep, your breath when you sleep and any moisture from any cloths you sleep in.

If you fail to keep rule 1 your sleeping bag will not be as effective as it could be.

Second Rule: Pick a camp site with low humidity. That will keep things less clammy and warmer.

Third Rule: Keep some ventilation going around your sleeping bag - keeps things dryer.

Forth rule. Sleep under some cover. Double walled tent, bus shelter, tree (if its branches don't fall on you) keeps you warmer.

I'm sure there are more .. but I cannot think of them at the moment.
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Re: Feeling clammy when sleeping in cold weather

Postby Huntsman247 » Sun 22 Jul, 2018 4:43 pm

neilmny wrote:
north-north-west wrote:Thanks to the physics geeks from here too.

And thanks to Huntsman for raising this one. It happens to me sometimes when I sleep in the car and I've always assumed it was due to sweat from overheating, even though I've felt chilled. It's great to finally understand what's going on.


Holy crap can someone explain in dumarse terms what all this means.....we cretins need to understand too.
In summary our bodies constantly create vapour (sweat if our bodies overheat).
I figured that this moisture would pass through the bag as sleeping bags are breathable. But as has been brought out by the way that the sleeping bag works, if you push the sleeping bag past is thermal rating it is unable to keep the area directly around you warm enough to keep the vapours coming out of your body vapours. These vapours condensate on and around you. Leaving you damp as I and others have experienced. You survive and I could probably push the bag in even colder temps but it leaves you uncomfortable.

So even if you sleep somewhere dry, whether it be under an overhang or a night with 0 humidity if your bag isn't up to the ambient temp you'll still get clamy from your body vapours when cold enough.

I'm thinking you could probably get away with pushing the limits of a bag by throwing a couple hand warmers in the bag that can last the night. That they would produce enough heat possibly to keep the bag heated enough to keep the body vapours as vapours.
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Re: Feeling clammy when sleeping in cold weather

Postby Warin » Sun 22 Jul, 2018 5:14 pm

Huntsman247 wrote:
neilmny wrote:
north-north-west wrote:Thanks to the physics geeks from here too.

And thanks to Huntsman for raising this one. It happens to me sometimes when I sleep in the car and I've always assumed it was due to sweat from overheating, even though I've felt chilled. It's great to finally understand what's going on.


Holy crap can someone explain in dumarse terms what all this means.....we cretins need to understand too.


if you push the sleeping bag past is thermal rating


Strictly speaking the thermal rating is its R rating.

And that says nothing about its 'breathablity'.
For that you need g/m2 per 24 hour period. That is grams per square meter per 24 hours.

So the above should read "if you push the sleeping bag past it's breathablity "?

Beyond the R rating you simply get cold.
Beyond the breathability you or the bag gets wet .. and then you 'll get colder.
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Re: Feeling clammy when sleeping in cold weather

Postby Huntsman247 » Sun 22 Jul, 2018 5:31 pm

Warin wrote:
Huntsman247 wrote:
neilmny wrote:
Holy crap can someone explain in dumarse terms what all this means.....we cretins need to understand too.


if you push the sleeping bag past is thermal rating


Strictly speaking the thermal rating is its R rating.

And that says nothing about its 'breathablity'.
For that you need g/m2 per 24 hour period. That is grams per square meter per 24 hours.

So the above should read "if you push the sleeping bag past it's breathablity "?

Beyond the R rating you simply get cold.
Beyond the breathability you or the bag gets wet .. and then you 'll get colder.
Just trying to simplify it. But in my case its not the breathability of the bag. Not that it isn't the reason in some cases. But for the breathability to really be a factor the perspiration has to remain as a vapour. Otherwise it could be the most breathable bag in the world but your not addressing the root cause and would still be wet. So I don't think it should be 'past it's breathability'. I'm certainly not steaming when I sleep if it was breathability then this would occur even in warmer temps. I'm not using a bivvy sack. But yes it could be better written as 'past what its rated or designed for'.
As for the R rating correct me if I'm wrong but i haven't heard of a sleeping bag being rated with an R rating. It's usually rated by providing it's comfort, lower and extreme limits. That's more for sleeping pads and the like.
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Sun 22 Jul, 2018 8:09 pm

Huntsman247 wrote:In summary our bodies constantly create vapour (sweat if our bodies overheat).
I figured that this moisture would pass through the bag as sleeping bags are breathable. But as has been brought out by the way that the sleeping bag works, if you push the sleeping bag past is thermal rating it is unable to keep the area directly around you warm enough to keep the vapours coming out of your body vapours. These vapours condensate on and around you. Leaving you damp as I and others have experienced. You survive and I could probably push the bag in even colder temps but it leaves you uncomfortable.

So even if you sleep somewhere dry, whether it be under an overhang or a night with 0 humidity if your bag isn't up to the ambient temp you'll still get clamy from your body vapours when cold enough.

I'm thinking you could probably get away with pushing the limits of a bag by throwing a couple hand warmers in the bag that can last the night. That they would produce enough heat possibly to keep the bag heated enough to keep the body vapours as vapours.



Nailed it.

All I'd add is that the environmental relative humidity does come into play - You can have a 'dry' night that gets cold enough to just chill you, without the clammy sweat/condensate. It's just that commonly, if youre in an alpine area, the temperature drops are enough to really push the relative humidity up, even if it was a 'dry' day.

The handwarmer idea is a good one. I sometimes heat drinking water bottles for the footbox. As mentioned in another thread, going for a small tent to trap a small bubble of warmer air around you is another option, but you're then almost guaranteed to have epic condensate on the inner tent wall then.

Warin wrote:So the above should read "if you push the sleeping bag past it's breathablity "?

Beyond the R rating you simply get cold.
Beyond the breathability you or the bag gets wet .. and then you 'll get colder.


No, sorry, not quite.

Sleeping bags are already pretty darm breathable. But 'breathability' of a given material only comes into play if the present moisture is in vapor form, ie evaporated. Which only happens if the air isn't at 100% relative humidity (ie can carry all present moisture as vapor). Which only happens if the air is warm enough. Which only happens if you have a good R value.

Ergo, beyond a suitable R value for the conditions, the air gets too cold, hits 100% relative humidity, perspiration doesnt evaporate into vapor, and it doesnt matter how breathable your jacket or bag is, that moisture wont really go anywhere.
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Re: Feeling clammy when sleeping in cold weather

Postby north-north-west » Wed 25 Jul, 2018 8:15 am

All this sciencey stuff has got me thinking (never a good idea) about the 'wet foot' phenomenon with the sleeping bag.

Now, the idea of it being from vapour emitted by the feet overnight, passing through the bag and collecting on shell doesn't make sense to me. Maybe thatt's because I don't know enough about the science but . . . with poor peripheral circulation especially, wouldn't the majority of the vapour be from the torso and, therefore, the outer dampness (and I'm talking about those mornings with the shell wet when the inside is dry) should be more on the upper area than around the foot.
So . . . but with warmth being transmitted (for want of a better word) through the inner lining and the insulation into the shell material, if the feet are colder and the torso/head area warmer (and this could be exacerbated by the greater dead air space around the feet), could there be a sufficiently significant temperature differential between the material of the outer shell in those areas for vapour inside the tent to condense on the foot rather than elsewhere?
It seems logical to me, but I don't know enough about how this works. Does the science contradict that?

(edit just to tidy up the tyypos)
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Wed 25 Jul, 2018 9:25 am

north-north-west wrote:All this sciencey stuff has got me thinking (never a good idea) about the 'wet foot' phenomenon with the sleeping bag.

Now, the idea of it being from vapour emitted by the feet overnight, passing through the bag and collecting on shell doesn't make sense to me. Maybe thatt's because I doon't know enough about the science but . . . with poor peripheral circulation especially, wouldn't the majority of the vapour be from the torso and, therefore, the outer dampness (and I'm talking about those mornings with the shell wet when the inside is dry) should be more on the upper area than around the foot.
So . . . but with warmth being transmitted (for want of a better word) ing through the inner lining and the insulation into the shell material, if the feet are colder and the torso/head area warmer (and this could be exacerbated by the greater dead air space around the feet), could there be a sufficiently significant temperature differential between the material of the outer shell in those areas for vapour inside the tent to condense on the foot rather than elsewhere?
It seems logical to me, but I don't know enough about how this works. Does the science contradict that?



Yep, you're pretty much on it.

The footbox of the bag, having less meaty warmth inside it, is the most likely place of the bag to hit dew point first (assuming uniform insulation distribution, which often isn't the case, but the rule still holds (usually).

The point here is that it's not a case of vapour from one given source or another that's more likely to condense there. Its more a case of 'what is the general distribution of humidity owing to mixing of various sources and environmental conditions, around the bag shell, at a given temp?'.

If you were sleeping in the atacama, but went to bed with a humidifier in your footbox, enough of that vapour would seep through the bag, to increase the humidity in the air around the bag skin, despite the environment being very very dry. The temp may stay at the same, but the humidity added to this cold air saturates it , and bam, droplets on yo foots, everything else dry. Its would LOOK like they 'fell" onto the bag, because the drops precipitate on the colder outer surface (hence the frequent misunderstandings).

Conversely, hypothetically go to sleep in an alpine bog, with some icebags and a vapour liner round your feet, you could have a footbox that emits NO vapor, but becomes so cold compared to the environment, the already present cool, humid air would condense out on the bag skin too. Both inner and outer conditions contribute, its about where the equilibrium winds up on a given night

So, getting back to the real world, what we have is a combination. The feet aren't armpits, but they do sweat. For some more, others less. The footbox is part of the overall bag inner too, so unless you're in a VBL, its pretty much a given that the relative humidity inside the footbox is going to be higher than environmental after a few hours. Its also a given it will be warmer. Less so for some, but even if you *feel* like your feet are cold***, they're still warmer than outside. So - there will be SOME humidity elevation around the bag skin due to escaping moisture..

Does this form drops? Depends - on whether you reach dew point for that particular air sample, with whatever temp and RH it has due to the combined effects of foot temp and vapour, meeting and mixing with the environment

. If your foot vapour was adding to an already very humid air, then it may well condense with no temp drop. In this case, you may not see any on the bag skin of the body, because its warmer and thus keeps the air able to hold that higher moisture content.

Similarly, if the temp drops, the footbox (having less meaty heaty bits) will hit dew point sooner and you get drops. However even the chilly feet are pushing out more sweat than say your pack, so it remains dry - the air around it isn't as close to 100% RH and would thus need to be colder for droplets. Although its likely that yourdoarm breath rising to the underside of the tent skin will also condense out up there - the tent skin is even colder than the footbox, so it can chill air easily to dewpoint. If you tuck your bag close to your chin, you'll get dampness around there too - super moist breath needs muuch less cooling to reach saturation. And indeed breathing for long enough will increase the RH inside the whole tent, which of course also contributes to conditions at the bag skin, so you may even increase the RH enough to provoke condensation on the whole bag.


***having feet that *feel* cold is another matter. Unless you're a corpse, they're still comparatively warm. They just resupply that heat far slower than elsewhere, especially horizontal, so other tiisue and nerves stay cooler. Meaning extra insulation often won't do anything - its supply that's the issue, not loss. If cold feet an damp footbox are a chronic problem, carry a small plastic bottle (old peanut butter jar) in a stubby cooler. Fill with boiling water, wrap in dry socks. Slow release heat source increases effective heat supply. Needs to be slow, or although your feet feel warm at first, you dump most of that heat into the insulation, which of course just bleeds it outside in a few hours.

If you want to go REAL toastyfoot, combine this with a garbage bag, and stick the bottom 1/3 of a foil emergency blanket to the insid of it with double sided tape. Line the bottom of your bag/quilt with it, wear some thin wicking merino socks. All up inc PB jar, its only abou 200g and will make a maaasive differnce. Should all but eliminate footbox condensate, and if you get cold feet after doing that, see your doctor,- I suspect you are in fact the undead.

Make sense? Sorry these turn out so long, but I find if you gloss over stuff or don't flesh out examples it just confuses people more
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Re: Feeling clammy when sleeping in cold weather

Postby north-north-west » Wed 25 Jul, 2018 9:38 am

If I read that properly then basically I'm thinking right, it's just a lot more complex than what I wrote.
Good and thank you. Now to try the vapour barrier on the feet thing and see if it helps. Or maybe get a foot transplant. (Which makes me wonder what would happen to someone with a prosthetic leg/foot. Would they have even more of an issue because of less warmth, or would the lower surface area lead to less perspiration and thus less vapour . . . )
"Mit der Dummheit kämpfen Götter selbst vergebens."
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Wed 25 Jul, 2018 10:16 am

Both!!

Its complex stuff! Essentially weather forecasting for your own microclimate. Just be thankful you don't have to do.it for a 60000ft column of air! And then have everyone complain that the fog cleared by 10 am but 'YOU said it'd clear by NINE Am!!!"....

Its often very hard to predict. More realistic is to observe, understand and then react, if you're having repeated issues.

What problems are you having, and with what sleeping rig?
Last edited by jdeks on Wed 25 Jul, 2018 10:24 am, edited 1 time in total.
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Re: Feeling clammy when sleeping in cold weather

Postby Warin » Wed 25 Jul, 2018 10:20 am

north-north-west wrote: would the lower surface area lead to less perspiration and thus less vapour . . . )


less vapour = less water.. if it still hits dew point it will still give you liquid water.
Instead of one cup you get half a cup. Still wet though. :cry:

With both gone you could use a shorter bag ... though putting on cold legs in the morning will be like cold boots .. except higher up.
Though wet boots would not be a problem. :D
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Re: Feeling clammy when sleeping in cold weather

Postby north-north-west » Wed 25 Jul, 2018 10:34 am

jdeks wrote:Its complex stuff! Essentially weather forecasting for your own microclimate. Just be thankful you don't have to do.it for a 60000ft column of air! And then have everyone complain that the fog cleared by 10 am but 'YOU said it'd clear by NINE Am!!!"....

Ohhhh, are you the forecaster who said two days ago that it will be good and mostly dry weather at Cradle Valley/New Pelion from Thursday through Saturday but has changed it today to being continually *&%$#! right through?

What problems are you having, and with what sleeping rig?

It's always happened in the tent, with every sleeping bag I've had, though it depends on how much ventilation the tent is getting. Enough of a breeze and it doesn't occur, but without that good steady through breeze I almost invariably wake up with the outer shell of the bag wet at the foot. The degree of dampness varies, of course.
Usual sleeping rig is possum wool socks (plus down booties if I'm snow camping), and merino thermals top and bottom. The booties/socks come off if the feet start getting twitchy, but that doesn't affect the external damp. (Very sensitive feet. Very difficult feet in so many ways.) Warm enough weather (which is rare down here 'cause I'm a very cold sleeper) and the thermals might be removed although I'm more likely to just open up the bag to regulate the temperature.
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Re: Feeling clammy when sleeping in cold weather

Postby Huntsman247 » Mon 06 Aug, 2018 3:02 pm

Just got a new upgraded sleeping bag. Shout out to jdeks. He had a few new sleeping bags from a trip that never got off the ground. Just got it today, an unused, tags still on it, mountain hardware phantom flame. Trying to get out and try it in the next week and will report how on how the claminess goes.

jdeks has a few more sleeping bags and mats if anyone is interested.
He's got bags from about 5+ to -12 and a -7 quilt but its 2nd hand...
DM him if you're interested.

Anyways I received my bag in excellent condition and thought to give others some peace of mind if anyone's looking to buy a new sleeping bag.
Cheers jdeks.
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Tue 07 Aug, 2018 3:49 pm

Huntsman247 wrote:Just got a new upgraded sleeping bag. Shout out to jdeks. He had a few new sleeping bags from a trip that never got off the ground. Just got it today, an unused, tags still on it, mountain hardware phantom flame. Trying to get out and try it in the next week and will report how on how the claminess goes.

jdeks has a few more sleeping bags and mats if anyone is interested.
He's got bags from about 5+ to -12 and a -7 quilt but its 2nd hand...
DM him if you're interested.

Anyways I received my bag in excellent condition and thought to give others some peace of mind if anyone's looking to buy a new sleeping bag.
Cheers jdeks.


Thanks :) ZPacks quilt is gone but yep, if anyone else is having similar issues, I've got some spare gear that may help it.

Let me know how that bag goes - I'll be VERY surprised if you wind up cold and clammy with it!
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Re: Feeling clammy when sleeping in cold weather

Postby GPSGuided » Tue 07 Aug, 2018 4:46 pm

Huntsman247 wrote:I've never really noticed this before but last couple of trips I've slept in around -5 and have had to cinch up the bag around my head. I was warm... just but not hot. I'm a cold sleeper. But I woke up each time around 4.30am feeling cold and clammy needing to drape my jacket over my body and seem to feel slightly cold and rather damp till I wake up...
...
I've researched this a bit and most people say that your too hot and therefore sweat but I'm just feeling warm.

Such a convoluted discussion in this thread.

I think Huntsman247 answered his own questions in the first post. If you are feeling cold and you weren't sweating (which you should be able to differentiate), then it's condensation. It's not exactly difficult to know whether one is sweating. As such, it's more than likely a case of inadequate warmth in the sleeping gear.

The other consideration I'd consider is Huntsman247's health. Given non-event in the past with the same setup and condition, a sudden change in one's ability to adapt to the cold is suggestive of some body changes. May be time to do a general health check with the GP. Certain health conditions may bring this and similar on.
Just move it!
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Re: Feeling clammy when sleeping in cold weather

Postby ribuck » Wed 08 Aug, 2018 4:42 pm

GPSGuided wrote:
Huntsman247 wrote:... a sudden change in one's ability to adapt to the cold is suggestive of some body changes ...

I've noticed a gradual change as I aged. When I was young, there was a huge gap between the temperature at which I felt cold and the temperature at which I sweated. Now, there's almost no gap. I need to adjust my bedding several times during the night (unzip/zip sleeping bag) to avoid sweating.
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Re: Feeling clammy when sleeping in cold weather

Postby Huntsman247 » Sun 12 Aug, 2018 7:15 pm

Ok. Just got back from a trip. Jdeks was spot on. Conditions wasn't quite as cold but it still was well below zero, really windy and raining all night. Rather miserable actually.
Anyways, woke up dry and not clammy! However I did notice a little bit of condensation on the inside of the outer fabric. Although I suspect that it was more due to how much moisture was in the air. Or the fact that I had the bag half unzipped till I woke up in the mid morning a bit nippy and zipped it up. Either way the original bag was definately not warm enough for the conditions and my body temps. Thanks to everyone's thoughts!
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Re: Feeling clammy when sleeping in cold weather

Postby jdeks » Sun 12 Aug, 2018 8:54 pm

Huntsman247 wrote:Ok. Just got back from a trip. Jdeks was spot on. Conditions wasn't quite as cold but it still was well below zero, really windy and raining all night. Rather miserable actually.
Anyways, woke up dry and not clammy! However I did notice a little bit of condensation on the inside of the outer fabric. Although I suspect that it was more due to how much moisture was in the air. Or the fact that I had the bag half unzipped till I woke up in the mid morning a bit nippy and zipped it up. Either way the original bag was definately not warm enough for the conditions and my body temps. Thanks to everyone's thoughts!


Sounds like properly pleasant hiking weather.

Subzero + rain basically guarantees dampness somewhere in/on your bag. No real way around it - air is already close to saturation (due rain), and once you heat up what air is inside the bag, add some more human water vapor to it, then cool it down as it moves out through the bag, it's going to hit dew point .

Only solution would be a vapor barrier liner, but that may note be very comfortable in damp conditions. Failing that, just dry the bag when the sun comes out.

Glad the bag kept you comfortable though :)
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