Sweating and chilled while sleeping

Jonathan,

What kind of temperatures were you experiencing the nights that you were cold? Were winds high and what was the approximate humidity? Also, what sleeping pad and length were you using? Do you tend to sleep cold? I can’t remember Western Mountaineerings temperature rating of the Ultralite.

Rich

Rich,

Temperatures were probably about 35 degrees. (flost was on the ground in the morning) Wind was pretty minimal. Humidity was low, I think. (We were in the Sierras around 11,000ft.) My pad was 3/8 in. blue foam, about 1/2 length. (I used my backpack for my feet.) I normally sleep pretty warm. And the Ultralite is rated as a 20 degree bag.

Jonathan could you post your gear list?

Most consider the WM bags to have a conservative rating,so a 20 degree bag is what others would call a 15 degree bag. In other words, your bag was too warm.

>>”damp…sweat”

just a guess, but it sounds like you might have been overdressed. sweating is usually the body’s response to being too hot. in some cases, eating a foodstuff or taking a dietary supplement, or wild herbs/plants (e.g. boneset tea), or prescription drug, which is a diaphoretic will cause profuse sweating. did you consume anything that was a diaphoretic? were you coming down with something that you fought off? got all bundled up and into the bag before cooling down?

just some thoughts. think about it. you’re the best one to figure out if anything mentioned above fits your situation.

Guess only.

If you are still sweating when you turn in then you may not have stoked the furnace by eating a hardy meal.

Second guess is sleeping pad is too low an R value.

Crunch the numbers:

canister 2#
water 4#
food at 1.5# per day 15#
base weight 6#

For me 1.5# of food for 20+ miles days is not enough after a couple of nights.

I agree with many of the posts already made. You may not have had sufficient food, the sleeping pad may have been insufficient, and the sleeping bag may have been too warm. You may find that a thicker and longer sleeping pad like the Gossamer Gear Nightlight Sleeping pad would help.

I believe that with frost on the ground the outdoor temperature was probably below 32 degrees F. This is begining the temperature range to consider wearing Vapor Barrier Clothing to prevent wetting out your sleeping bag (as those available from Stephenson’s -www.warmlite.com). With continued nights of colder temperatures and without airing out your WM Ultralite Sleeping Bag you may lose loft of the sleeping bag as well.

Rich

This happens to me. Apparently,  when you start an new intense workout routine, you can experience night sweats. Even if you are experiencing normal temperatures. This is because the increased metabolic rate activates and sustains the calorie burning functions of the body, even while it is resting.

When I wake up cold and sweaty, I find that getting out of my bag and standing outside helps reset my thermostat and I can go back to sleep and be fine the rest of the night.

When this happens I typically have gone to bed a little chilled and over dressed along with being buttoned up too tightly in my quilt. It also occurred more frequently when I was on a pad with insufficient R value.

I am not sure about the bag being too heavy.  The Ultralight is a good bag at around 20F…a bit more than needed. As you sweat, the down should pick up some humidity causing it to collapse a bit. This will usually decrease the insulating value of your sleep system, so, it doesn’t sound like it was out of range or overly warm.  I suspect that you were perhaps overdoing it with the bag at the start of the evening.

I think half the problem could be your metabolism is too high when you turn in. By zipping things up, you have no way to ventilate excess heat/moisture and you sweat. Some is insensible perspiration, about a cup or so overnight. You cannot do anything about this. The other part is from overheating to cool you off. This part you can avoid at 35F. Simply open up your bag and leave it that way, maybe with only your foot box partially zipped. This allows you to produce a heck of a lot less sweat for the first part of the night, and, you will sleep cooler. As the night gets cooler, you can zip the bag up. This avoids the cooling sweat from your body saturating the down early on, leaving it damp and collapsed. You will find that sleeping warmer is not always an advantage, sometimes you need to cool off some for the first few hours (just before dawn is the coldest, normally.)

At 30-35F, you should have been fine. You had an over rated bag for 30F. You were in a tent. You did not have much wind. The air was fairly dry. But, the thin pad will take away about 10-15F from the bag.  I suspect this is the other half of your problem. The pad is a bit thin, you really want around an R3, say an Xlite or equivalent. Roughly, this is: 30F/R3, 20F/R4, 10F/R5, 0F/R6+.  While an Xlite would work well, it is also quite expensive, in terms of weight and dollars. On the hills, you really cannot avoid packing a good pad. Adding more pad in either case will cost between 8-12oz. A Luna pad from Nunatak is about $45 and will work well down to 40F. (This is identical to the old full length GG Nightlight pads.) The Xlight will still cost you the 12oz, but will keep you comfortable down to 27F or so with additional pads…at $180.

Basically, the sleep system you describe is out of balance. What you have a 20F bag and an R1 pad is not enough for 20F temps. While it is true that WM makes good bags, they cannot compensate for the lack of ground insulation at 30F. My daughter froze one night when we hit 40F. While she had a 32F bag, she didn’t bring ANY pad. A 20F bag really wants an R4 pad to hit 20F comfortably. Actually, that is the way ISO/EN tests them.

Thanks.

We were all young and silly way back then.

Much older now.

(because we are all busy , I’ll explain : the question was asked 14 years ago)