Addressing ground-side breathability problems while sleeping

[Ian Schumann]

Okay maybe that's a mouthful of a title, and not particularly clear yet.

What I mean by "ground-side breathability while sleeping" is this …
The human body perspires, at very least insensibly, 24 hours a day. Additionally, body heat drives out trapped moisture from our clothes throughout the night. At home, this isn't a problem. Most of us sleep on linen or cotton, which are highly breathable, and so any moisture moving outward is easily dispersed within the mattress, pillow, sheets, and eventually the surrounding air.

On trail, there is a problem with this. Most of us sleep encased within various layers of different varieties of woven plastic, an inherently non-breathable material. Sure, when under no great pressure, a lightweight open-weave Capilene top might breathe pretty well. But, when that polyester fabric is pressed between your skin and the totally air-tight nylon shell of your sleeping pad, my guess is that it compresses and becomes basically useless for dispersing moisture.

Thus, being a mainly side- and stomach-sleeper, night time for me is actually a relatively sweaty part of any backpack trip I might take. Worse, I wake up after a night of tossing and turning significantly more dirty than when I went I went to sleep, because of build-up of sweat and oil particularly on my face and around my torso. The issue is compounded if I've worn a puffy jacket to sleep, because any part of the jacket that is underneath me gets compressed down into a simple double layer of tightly woven nylon.

Granted, this problem is minor. On backpacking trips, you simply get dirty and that's how it goes.
But, it's surely a nuisance, and I'd like to solve it.

I suspect that back sleepers may deal with this problem less. It's also possible that less hot-natured or sweaty-natured people will probably deal with this less.

Anyway … I'd love to figure out how to solve this or at least mitigate the problem.
I'm switching to merino base layers, which should help at least a little. But I still have this problem of sleeping on what is essentially a non-breathable slab of plastic, and perhaps that's the main issue. I suppose the second main issue is that an inflatable pillow of any kind is also inherently non-breathable. Sleeping on my side or stomach means my face is on the pillow, and a *lot* of oil and sweat comes off your face.

Anyone ever gotten irritated with what I've described above? Also, has anyone found a way to convert or cover their sleeping pads (or pillows) with something (an interface of some sort) to make the experience of sleeping more breathable and thus comfortable?

Okay, discuss and have fun. Thanks.

[mtnwkr +1]

I too am a stomach/side sleeper and have been irritated by the clammyness of sleeping in synthetics. I notice I sleep best on a ridgerest pad and that the little "ridges" are full of water(sweat) when I wake up. Closest thing to breathable I guess. But not nearly as comfy as my other pads.

[Heath Pitts]

I have used a thermarest trekker lounge chair cover with a NeoAir large the last couple of trips and I noticed that I was definitely less sweaty than normal. I always wear merino to sleep in as well. The lounge chair also has a fleece pillow insert where I place an inflatable pillow with a down vest or jacket that I'm not using on top of the inflatable. Less sweat there as well at least for me. I use a quilt while sleeping.

This is definitely not a light option but I took it because we were base camping while fly fishing and I wanted the extra comfort. Thermarest also sells pad covers that I think are made out of the same material as the top of the Trekker. Might be wrong.

[Ian Schumann]

MtnWkr,
I'm switching to a Klymit Static V as my main pad — accepting the higher weight and all — so hopefully the ridges in that one will make for a similar boost in "breathability".

Heath,
Interesting you mention that — I wasn't aware that thermarest made anything like that. I'll have to check around and see if anybody clever has made some kind of lightweight coolmax or silk fitted sheet kind of thing that can be used over a sleeping pad. At very worst maybe I'll just have to create one myself.

[Jennifer Mitol]

I just started using quilts this summer and actually posted a similar question back then…although at the time I didn't realize that this really was my question. I am also a side/stomach sleeper and every morning the top of my exped is literally stained with moisture (er…sweat). I started using a silk liner as a sleeve for my exped and it helps a little; I'm considering just turning it into a fitted sheet (I move around enough to get tangled in it too often).

The klymit inertias look promising, but you need a full bag for those to properly work. Next I was going to try a ccf (1/8th from GG) on top of the exped for added warmth and see if that helps the moisture management problem.

But I'm certainly looking for more ideas….

[Nick Gatel]

If you are sweating you are too hot. Remove layers or vent your bag/quilt. Insensible perspiration will not be noticeable if your climatic controls are dialed in.

[Colin Krusor]

I would agree that it seems to make sense that one could completely avoid excessive sweating at night by "dialing in" their sleeping system, but I often don't succeed at this. And I have warm and cool weather quilts, each with lots of venting options.

I'm a side sleeper and I blame the clamminess of a sleeping pad surface damp with sweat for the poor quality of sleep that I often get while camping. I have not found a lightweight solution to this.

My heavy solution is somewhat effective. I undid the weight savings I achieved by going from a sleeping bag to a quilt by adding synthetic insulation on the top of my sleeping pad. I sewed a trimmed cotton bedsheet to a layer of 2.5 oz climashield apex, and sewed those directly to the excess material of the perimeter seam on my Exped Synmat UL7 pad. Now the surface beneath me is a little bit absorbent, and there is a "breather layer" of polyester fiber insulation between the cotton sheet and the plasticky surface of the pad. I still find that I get a bit clammy sometimes, but it is an improvement over the bare pad.

[Raymond Estrella]

OK, my tongue is kinda in cheek, but I am a side-sleeper and rarely have any of the issues you describe. But like others suggested I take a sleep system rated for the temps I expect to see. Then I have my down sweater or parka if they drop too much.

There is no reason to sweat at night. Yes we perspire all the time, but not running-down-our-body sweating.

I use a quilt down to about 0 F. Below that is a bag and I don't sweat at -20 much…

Good luck with it.

[Jennifer Mitol]

My tongue is also in my cheek a bit, but Raymond, you are not a perimenopausal woman. We sweat no matter what.

[Raymond Estrella]

Ha, I was addressing the OP Jen. I don't want no trouble with a perimenopausal woman. ;-)

[Jennifer Mitol]

What are you sayin, Ray??? You think we perimenopausal women have problems?? Eh???
Look, now you've made me cry…

Lol……..

[Raymond Estrella]

Chocolate is on the way…

[Clint Hollingsworth]

Maybe a set of cotton long johns? For sleeping only?

[Jennifer Mitol]

Which as a stomach/side sleeper might also account for a fair amount of – er – liquid on the pad. I woke up in the middle of the night once to find myself drooling like a 9th grader asleep in study hall. Good thing I was only sharing the tent with CharlieDog…that HAD to have been an attractive sight…

[Matt Dirksen]

I always sleep in lightweight cotton pajama pants and a cotton tee shirt, and roll it up with my bag & pad to keep it away from the rest of my clothing. It is equally as important to have an effective way to disperse presparation as it is to have good vapor permeability. When I sleep on my side and I don't have cotton pants on, I discover that the first place I start sweating is all along the inner sides of my legs where they contact each other. This never happens with cotton. I've tried synthetics in the past, but they tend to stink up quickly, become less permeable, and loose their ability to disperse any presparation from that point on. Besides, I try to support the "natural" fiber and insulations as much as I can, and where it's practical.

It can ge quite muggy during the summer here in the mid-Atlantic, and so I don't go overboard on the insulation. If its balmy and never going to be below 50 at night, a light blanket might be more than enough. Regardless, the cotton has always worked for me and has been "worth" the weight. I also used an old luxury edition therm-a-rest for many years, which has a fleece-like surface. This always allowed me to easily sleep directly on the pad. I have a Neorest now, but am not really used to it as of yet and have over inflated it a couple times, leaving me with a major backache in the morning.

Hope this helps,

Matt

[Ian Schumann]

Hmm looks like the 'watch' alerts have stopped reaching me, so I missed a lot of activity here.

Anyway, a few notes for those that are still interested:

1) I disagree with the proposition that there is no reason to sweat at night.
Anyone ever used a vapor barrier? I personally haven't, but I know what non-breathable plastic feels like. One needs to vent a VBL system due to buildup of moisture, regardless of whether your sleeping system is 'dialed in' for the temperature at hand — correct, no?

What I'm contending is that for the parts of your body that are pressed up against non-breathable synthetic materials while sleeping, what results is basically a small micro-climate that acts very much like a vapor barrier. This is the very same reason that someone mentioned sweating between the legs, even when the rest of your body is perfectly comfortable or even cool.

This is the same reason that dispersion of moisture was mentioned, I suppose. The issue is not that sweating is caused by too much insulation — though that is possible — but instead simply that the body's natural insensible perspiration builds up in certain sleep positions to the point that it becomes, well … *sensible*.

2) This being said, I like the ideas about using either cotton sleeping clothes or a cotton sheet. Anyone have any suggestions on what kind of cotton sheet (the term feels generic to me) might best accomplish the absorption / dispersion of moisture?
I'm going to see if I can't rig up some kind of velcro situation with my new pad. I want to avoid sewing the sheet directly to the pad because I'd sure like to wash it every so often.

I see with these modifications that my sleep system is going to get heavier, but … as many have said before me, one of the benefits of going UL with most of one's gear is that you can then afford to go heavy — if you wish — on a couple of items of great importance. I've determined that sleeping while backpacking is the part of the trip that I enjoy the least, so I'm going to try dealing with 0.5 – 1.0 lb of added weight in order to enjoy my nights a hell of a lot more.

… discuss, discuss …

[Jason L]

Ian, I just ran across your thread and was wondering how you've been making out with the use of cotton?

[Matthew Reese]

A cheap pair set of cotton scrubs work well as camp/sleep wear, though obviously not ultralight.

[Ian Schumann]

Hey Jason,
Yep, back a few months ago when I was still puzzling over this, I did a couple of things:

1) Switched to all natural-fiber next-to-skin layers. Well, mainly I just ditched my synthetic tees entirely and went all-merino. The legs don't sweat much so I didn't worry about that. But I got an Ibex Indie over the holidays and I've been using that exclusively next to skin at night, which has helped.

2) I stopped wearing unnecessary insulation to bed. That is — the two trips I've taken since this OP both had overnight lows in the 40s or high 30s at the worst. For those temps, a base + mid layer, hiking pants, and warm socks are all I need. Quilt goes on top. No puffy jacket inside. I believe that previously I was simply over-insulating with my puffy jacket.

3) I took an old and somewhat well-used piece of twin-bed flat linen sheet, and nicely asked my wife to make some modifications. We cut down the sheet to be the size of my pad (Klymit Static V, rather large), and then she installed a couple of simple strips of elastic, running laterally on the underside of the sheet, one near the head and one near the foot of the sheet. This way, I can slide the sheet over the top side of my pad, properly fit in the elastics at the top and bottom, and the sheet stays on my pad rather tightly all night.

This last one has probably been the single biggest improvement for me. With the cushy Static V pad it *almost* feels like I'm sleeping on a real bed. Since I sleep on my side or stomach, a lot of my most tactile parts (hands and face, that is) are in contact with the pad. With the breathable linen, it's real comfy and I've enjoyed fairly sweat-free nights as a result of all the changes noted above.

Hope this is helpful!

[Jerry Adams]

"I stopped wearing unnecessary insulation to bed."

I think same thing

It's like when you're hiking, you don't want to wear extra stuff or you'll sweat. Same thing when sleeping although not as bad. Leave sleeping bag unzipped until middle of night when you get cold. Have a couple extra things handy to put on if you get cold, like hat or vest.

[Steve Meier]

Thermarest makes synthetic pad covers for the NeoAirs that feel like cotton to the skin. I use the covers whenever it is going to be warmer at night and I won't be wearing long sleeves or long johns at night. It has been worth the 6 oz for comfort and sweat-free nights from not laying directly on the pad. Along with a quilt and all of its venting qualities, I have eliminated the dreaded sticking to my pad.

[Hiking Malto]

"Anyone ever used a vapor barrier? I personally haven't, but I know what non-breathable plastic feels like. One needs to vent a VBL system due to buildup of moisture, regardless of whether your sleeping system is 'dialed in' for the temperature at hand — correct, no?"

No, you should not sweat in a VB suit. If you do then you have too much insulation. The intent is for your body to produce a high humidity environment not sweat. As for your original scenario. I am also in the camp that you have too much insulation. I believe you should always go to bed knowing that you will need to add layers. Why? I tend to hike and then immediately go to bed. It takes my body a while to cool down and if I wear the final insulation layers then I will sweat, have condensation and end up a tally being cold.

[Jason L]

Good stuff.

My wife and I use VB socks (made from trashcan liners) frequently while backpacking. We really like to use them. They keep our feet warmer, nice and moist, but not wet once. But, we hike in sandals when we're not in the snow.

Good to see that you figured out a solution for your problem. Using a cotton sheet sounds like it would do the trick, but for the downsides. I've also heard that schoeller dryskin is very good for wicking and dispersing moisture without the added weight, perhaps?

I used to wake up in the middle of the night uncomfortable from sweat building up in my nether region. A scrap of cotton fits the bill very well.

By the way, I remembered that there is a "watch this thread" doodad on the top of this thread that one may click to watch the thread. I forgot all about those.

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