Why am I so cold?!

[Bri W]

All of my labs were normal. No anemia, thyroid, or hormone issues that I know of. No chronic conditions. Other than recent back surgery, I’m very healthy. Just run cold, I guess. ?

[Matt Dirksen]

“So despite a high R value, the XTherm isn’t considered an insulated pad? Excuse my ignorance on this subject, but why is the UL7 a better 4-season pad than the XTherm?”

In my opinion, they are both considered “insulated” pads, since both Exped and Cascade Designs label their pads with R-values. Some folks may argue that since the XTherm doesn’t have any infill material inside of it to contribute to it’s overall R-value, that somehow this means it’s not an insulated pad. I don’t see it that way. That’s like saying the R-value of my home’s walls is R-19, since I’ve put R-19 insulation into the wall cavities. What about the Siding, the sheathing, the Tyvek, the drywall, and the thermal bridging due to framing material? The whole is not always the sum of it’s parts.

Analogy aside, given your particular situation, I would not even think twice about making sure I had a good ccf pad in addition to the Xtherm if I were going to camp in temperatures approaching freezing. I think the “insulated air mattresses” are great, (and as others have said), but until there is some established “EN Rating” system for sleeping pads, and the pad manufactures agree to actually measure their pad’s R value at sub zero temperatures and variable forces applied to them (aka, side sleepers), there’s no real guess how insulative an air mattress actually is at temps under freezing. Air (especially moisture-laden air) does strange stuff as the temperature drops.

 

 

[Anonymous]

You can test technically within normal, and still be lower than ideal in those areas.  Even though my spouse now tests within normal for thyroid, i would say her thyroid is still a bit sluggish and not up to par, as she has a hard’ish time losing and keeping weight off.

Similar with anemia (which she tends to as well, but usually technically tests ok, but towards the low).   You could try upping your iron, phosphorus, and B12–it may make a difference (sardines are excellent for all of this btw).

But yes, women generally run colder than men–basically slower metabolisms and less overall muscle on average.   But your case sounds a bit more extreme, which may point to some kind of imbalance or at least less than ideal levels.  Or maybe you’re just really lean?   If so, putting on a little fat would likely help some too.  That’s why a lot of Polar animals have lot’s of fat (blubber).

Think Sumo type training–fit, but more bulk (both fat and muscle).

[James holden]

thermal resistance is thermal resistance  (r-value)

A long as the R-value is correct it shouldnt really matter what material is being used to insulate

air is an excellent insulator … in fact what down and synth does is TRAP AIR … thats what provides the insulation ….

the neo air just does it in a different way

the older neo airs were tested by BPL and proven to meet or exceed their R-values

;)

[Matt Dirksen]

”

“thermal resistance is thermal resistance  (r-value)

A long as the R-value is correct it shouldnt really matter what material is being used to insulate”

Hi Eric,

Unfortunately, it has been discovered that this not the case.  The condition is called the temperature dependency of insulation performance, which has impacted insulation manufacturers in the building industry over the past few years. In other words, even if the testing conditions between manufacturers were the same, and they could best simulate real world conditions, the R-value of the insulating material could very well change at varying temperatures. And depending on the insulation, it could vary significantly between cold and warm temperatures.

I know Roger and many others have done admirable work over the years, but time and time again, folks on a ccf pad always report feeling “warmer” than with an air mattress with the equivalent R-value. Putting real world conditions aside, I suspect temperature dependency may have something to do with this. I would be very curious if Roger & others could run the testing experiments at different ambient temperatures.

Perhaps it’s totally splitting hairs, perhaps not. But since we have a lot of gram counters on this list, and given all the marketing dollars spent by pad manufactures making R-value claims, I’d sure hope to see a level playing field someday soon.

[Bradford Rogers]

Matt, I will say that I have always found CC Foam to be very warm as well, much warmer than a self inflating mat of the same R-Value.

[James holden]

matt …

thanks for the interesting links …

but in the context of this thread and the xtherm i think the point is fairly moot …

when one is talking about xtherm alternatives, its really only down and synth (not foam) mats that are realistic, or at best a combination of an inflatable + thin foam … on those cases all those mats (down and synth) do is trap the air, they are all inflatable

now if one is talking about using pure foam mats then perhaps it may matter … for a 5-6 R value that would be quite bulky

but i dont really see how one air filled inflatable pad can be significantly warmer of another one of the same measured R value …

thermarest BTW does all its measurements at 39F

http://www.cascadedesigns.com/therm-a-rest/blog/r-value-meaning/

personally i have a prolite small at 2.4R and a solite small at 2.8R … i dont notice any difference except the prolite is easier on the back

;)

[Matt Dirksen]

Yup – I admit, it could be moot, especially with this particular thread.

But to be perfectly honest; my sinking suspicion is that manufacturers of air inflated pads will someday need to severely tweak their values, if sub-freezing testing were ever required, especially given that some rigid insulation products were recently found to lose up to 30% of their R-value between 75 and 25 degrees Fahrenheit.

And thanks for the T-rest blog link. (fwiw, I had dropped a comment about this specific issue into that blog about year ago, which resulted in some followup phone conversations with them. I had suggested they consider dropping their chamber’s temperature to 20 degrees to coincide with the “typical sleeping bag” rating. I understood back then they might try to look into it, but haven’t heard back. I guess that’s too much air conditioning… )

[Brad Rogers]

Bri-

Obviously you run very cool if you are wearing a puffy at 70*F.

I suggest a bag like the Marmot xenon. The Xenon is the women’s version of the Helium only heavier due to having 26 oz of down (it’s rated as a -5 bag for men). Women often run 10-20* colder than men and most “women’s” bags are rated for men, even most name brand ones.

I also recomend bringing a nalgene and some extra fuel and making a hot water bottle at night to put in your bag. It appears you have problems generating body heat and that will put some extra heat in the bag that it can capture.

Both of those are “heavy” suggestions but going light doesn’t mean anything if you shiver all night.

My wife is cold natured and she finds her Marmot Women’s Helium (now Xenon) warmer than a 10* quilt. I would go with a slim bag and don’t get one longer then you need as that leaves more dead air space for your body to have to heat.

As you have probably heard make sure you are hydrated and have eaten well prior to bed. You tend to run cold if dehydrated and you need calories to generate heat. I would also do some jumping jacks or squats (etc) before bed too.

[Roger Caffin]

My 2c.

The problem with static testing is that it does not really match actual use conditions. Yes, I used static testing for our survey of air mats:
https://backpackinglight.com/airmat_sotmr_part1_2011/
https://backpackinglight.com/airmat_sotmr_part2_2011/
and I could see where the problems lay. Subsequent field testing confirmed my impressions.

First of all, a major difference between foam and air mats is that the air mats can and will have internal air circulation. Air mats with nothing inside them can be really cold for this reason. Foam never has this problem.

But it gets more complex when you look at what the insulation is. The XTherm uses a few baffles to limit air movement and also, they claim, to limit radiant loss. Since the difference between the ground temp and your body temp is not all that great, relative to absolute zero (-273 C), the radiation effect is not going to be very significant. Interesting marketing idea, but poor physics. The trouble is that you can have significant air movement inside an XTherm when the sleeper makes any movement at all. And that air movement costs you heat with every wriggle.

Now, contrast the loose baffles in an XTherm with the layer of insulation in a UL7. Sure, you can have air movement in the UL7, but most of the insulation value of the mat is in the layer of synthetic insulation inside the mat. Air movement has little effect on that. The UL7 mat stays warm even when you wriggle around. The bottom line here is that while the baffles in the XTherm may be innovative, I don’t think they are very effective in practice.

But sadly it gets worse. When someone sleeps on an air mat, they make ‘dents’ in the air layer. Hips especially tend to get very close to the ground, even though most of the mat is still very thick. Shoulders can also sink way down. When the air layer gets very thin, the XTherm baffles are not going to be much use and cold will get through, but the layer of synthetic insulation in the UL7 will still be functioning just as well as in the test rig. You will stay warm.

I found the cross-ways air tubes on the XTherm to be a real problem. The sides of the mat would compress so easily, bringing my arm very close to the ground. I could feel the cold creeping in. The lengthwise tubes of most other mats, including the UL7, never had this problem. In fact, many mats have a slightly larger outer tube just to keep you on the mat and off the ground. This is smart.

Finally, in very cold weather, you can get condensation inside the mat if you blow it up with your mouth. In snow conditions you can get ice inside! This seems to have much less effect on the UL7 since the synthetic insulation is under the top side. Ice on the floor of the UL7 is little different fronm ice under the UL7, and the same applies to most other mats. But we never ever blow our UL7 mats up by mouth anyhow. We use a Pillow Pump and have no problems – and I use the the Pillow pump as a pillow for the night.

Yes, MSR has some interesting technology in places, but unfortunately it does not seem to work well in the field. A pity.

Cheers

 

[Roger Caffin]

I would also do some jumping jacks or squats (etc) before bed too.

At the end of a hard day, with bad weather outside the tent, and feeling very tired anyhow … hum … and anyhow, any warmth you might get from that will probably last for no more than 5 minutes. Work up a sweat – and freeze.

Cheers

 

[Jerry Adams]

exercise or hot water bottle will warm you up for a while, but after a few hours, when you’re at your coldest, the effect will be mostly worn off.

you could eat a little every few hours.  Like if you woke up and were cold.

mostly, if you’re cold, you need more insulation.  Doesn’t make that much difference where you add it.

If you have one spot where you have a lot less insulation, like maybe an air matt, then adding insulation there will be more efficient

[Bri W]

Wow, there’s a lot to sleeping pads that I didn’t know. Thanks for all the great info! I’ll see how my XTherm works with the Cuben bag and bivy. I have high hopes though that 0° longer quilt-turned-bag with 30% overall will make a huge difference, especially when combined with the XTherm.

I will most likely only be bringing cold food, but if a warm drink or food is needed, my grandpa and brother will have stoves/fuel.

[Roger Caffin]

It does not matter how good the quilt is if the mat under you is cold. However, see how it goes.

Only cold food though? No hot coffee? HORRORS! And a small problem too.

Cheers

 

[Bri W]

I don’t like cooking or cleaning dishes when I’m tired. That’s pretty much the only reason why; I’m exceptionally lazy. :) My grandpa will be providing the morning hot coffee, but I’ll likely just do instant cold coffee unless it’s an especially cold morning.

[James holden]

personally im not sold on neorairs being colder than other inflatable pads …

i owned the original neo air, the xlite, the prolite, and also various foamies … ive never had a real issue with the neoairs being cold for their R value

note also that outdoorgearlab tested both the xlite and xtherm extensively including using em on denali … and they dont have any issues, in fact its their top pick for a pad (they take no ad money, buy all their tested gear and will give bad reviews)

http://www.outdoorgearlab.com/Sleeping-Pad-Reviews/Therm-a-Rest-NeoAir-Xtherm

perhaps a neo air is “colder” than an equivalent R value synth/down mat, perhaps not … someone probably needs to test that scientifically …

in the meantime tons of folks use neoairs just fine for many many years

;)

 

[Bri W]

UPDATE:

I cleaned the Cuben 0° Epiphany and removed the excess material that made it into a bag so it could be a quilt again. I made it super lofty by adding lots of air. Then I slept in my backyard with my XTherm, my thinner Montbell wool baselayers, and Hoodlum…and I ROASTED! I had to let in drafts all night because of how clammy I was getting. It was WONDERFUL! My phone said it got down to 45°. The issues with this experiment were that  I was sleeping in a double-walled camping tent with the rain fly up and with another person sleeping next to me, so I plan to test out my new sleeping system further on Sunday in my bivy. Unfortunately, the low will only be 59°, so I’ll probably end up being uncomfortably hot. But at least I’m very warm below 50°!!! Finally! It might weigh close to 2 lbs., but I’m definitely bringing the Epiphany to the Sierras. This also makes me hopeful that I’ll be able to winter backpack in Oregon, assuming I bring along the correct clothing (maybe more VBL baselayers?) and equipment. But one trip at a time…

Thanks for your support, everyone!

[Roger Caffin]

Ah, warm weather… We have frost outside at the moment (in Oz).
But now you can start ‘pushing the envelope’.

Cheers

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