Originally Posted by Black Wolf
It depends on temperature .. as well as how long you'll be repetitively using your gear .. and the ability to dry it out. This is why Vapor Barriers work so well, they keep moisture from penetrating into your down and freezing there.
I'm gonna' technical on ya .. fabrics which are sealed are warmer because it prevents cold air blowing through to remove heat and it retains some humidity to reduce the evaporative chilling of your skin. Insensible sweat glands keep your skin moist for flexibility, even when cold. Highly porous clothes lose a lot of heat through convection and evaporation.
When insensible sweating cannot keep up with the excessive drying your skin gets dry and chapped. Your body constantly produces, and loses heat. If heat loss matches production you stay comfortable ... clothed or unclothed, increase heat production, you will overheat. Your body responds by perspiring , to increase cooling by evaporation. ( Perspiration > Evaporation > Condensation )
When the relative humidity in the air next to your skin is less than 100 percent moisture in your skin will continue to evaporate, cooling and drying your skin excessively. When humidity next to you skin reaches 100 percent evaporation stops, chilling stops, and insensible perspiration stops.
The air will only "accept" so much water vapor. this is why it condenses in your outer layer.
Staying warm in freezing to sub-zero temps is very technical .. long term even more so .. on average we lose 4 lbs of water a night .. 1/2 gallon.. that's a lot of moisture to manage even on an overnighter.
Staying hydrated helps keep you warmer .. dehydration thickens the blood and thus slows circulation.
Ok BlackWolf; to boil all of that down, can you just tell me at what temps it would be good to sleep in one of those sweaty suit things/or a trash bag with bread bags on my feet... and should I be naked to do it? If naked is better, then how does one handle mother natures calling at 4am? I can understand if in a sauna suit, but a trash bag would be tricky!
These aren't me being funny type of questions....they're real
Ohio just seems to have such borderline temps in the winter, with it really dropping super low late at night or early in the morning for just a small amount of time. It's that 35 to 20 area that frustrates me on what to really pack for, if you're only going to be in the 20s for a couple of hours.
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