Making a sleeping system warmer

John,

good breakdown in your Post.

i think implicit in the quote i used from Roman was that diuresis takes place resulting in bladder filling and then the urge to empty the bladder, and then the actual emptying of the bladder. at least that is how i understood it. but perhaps that was what i projected upon that statement from my own fading understanding of the human and animal physiology courses i took decades ago. however, Roman has a PhD in biology, so i think he knows this stuff far better than i ever did.

cold–> (BTW, i believe high altitude can also begin this series of events – at what altitude? i don't know).
vasoconstriction–>
greater blood/volume pressure–>
pressure detected by the kidneys(hormones involved??? can't remember, but they seem to control a vast number of physiological activities in the body)–>
need to make room for blood in the core of the body–>
increased diuresis–>
bladder fills–>
bladder shouts "Lucy, i'm home!!"–>
Roman rolls over in his quilt–>
Ready, Fire, Aim…–> (Roman, you got some 'splainin' to do"; now, we know the real reason RD finished the Artic 1000 alone)
Aaahhh….

at least that's how i read it.

sincerely,
Mr. Walnut

[Is there a Doctor in the house? Where are the MD's who read and occasionally Post to these Forums? I know they could do better than my failing memory. They've got to know this stuff 'cold' (pun intended). I reckon, this would constitute human phys. info and not giving medical advice. Maybe BD's presence has made them nervous, you know…, docs and lawyers. Doesn't sound like BD's a PI lawyer though. His appeal subject, that he mentioned, seems to make him one of the good guys. take that "PI" and also the "good guys" comment in the context in which it was written and not as an absolute.]

Andy:

Good subject matter. In addition to the above, you might try touching base with R.J. He wrote an article a few years back, which appeared on his old web page. It detailed his (then) approach to winter camping. In it he dicusses, in great detail, the mertis of 'light' down sleeping bags (both in terms of insulation & fabric thickness) as main insulation, suplimented with a thin synthetic insulated overbag. There's lot of other goodies in it as well. I believe the down bag was a WM Versalite (don't recall the overbag.

I realize the system, and, perhaps, the conditions may not quite be what you're driving at, but the concept may still apply. Perhaps the artlicle is still posted somewhere (also discusses clothing).

P.H.

> A friend who teaches survival to the army in Alaska said
of all the soldiers who came in with frostbite to the med
facility, all were very dehydrated. He thought that staying
hydrated fended off frost bite, but also said it may be
that frost bite could be causing the dehydration. He taught
his troops to drink lots in any case.

There could be a much simpler explanation than this.
For a start, in snow conditions the air containe very little water, and just breathing the air will suck water out of you. This is well known, especially for high altitude mountaineering. So anyone can get a bit dehydrated.

Soldiers who get frostbite are not handling the conditions well. This is not a criticism, just a statement of fact. Under these conditions it is not that likely they will be giving much attention to drinking cold water. So they may get more dehydrated. This does not mean that either *causes* the other.

However, the advice to monitor how much you drink (but NOT to excess!) is good in those conditions.

Andy,

Sorry for the late addition to this thread …

I bought the MB SS #3 about a year and a half ago. I find the comfortable limit is about 30 degrees … I've had it out in the open in windy conditions down to about 24 with my hiking clothes and a micropuff vest on. My toes and legs got mighty cold down that low.

The lowest I've had it was last March in New Mexico. A freak storm blew in and the expected 40 degree temps dropped to 8 degrees. I slept, though a bit on the cold side, in long Johns, my hiking clothes, my micropuff vest, a fleece jacket, a warm fleece hat, a pair of 200 weight fleece pants, and a pair of smartwool socks with fleece socks over them. I also had a fleece blanket field modified with safety pins and duct tape to act as a bag cover. My pad was a Insulmat Max Termo Mummy.

Since then, I have gone to the two bag concept. I have my MB #3, a homemade dwr nylon and silnylon bivy that has a velcro face closure that you can leave air holes in and breathe in the bivy, adding quite a bit of warmth. I also have a Ray Way 40 degree quilt to use as an overbag, although I now think that this is a bit of overkill unless you're looking for a bag with an effective top loft of 3.25 inches plus a Bivy, or the equivilant of about a 7 inch loft bag.

Another alternate setup I have is a my MB #3, my Bivy, my Micropuff vest, my Micropuff pullover (mine seem to nest nicely together), and a 12 oz 48 x 72 polargard blanket that I made with about .6 inches of loft that only comes up to chest level with the full footbox on the bottom.

I really like the #7 inside a #3 concept. The #7 would have an equivilant top loft of 1.25 inches … the two together should have an equivilant loft of a 6 inch down bag.