> It appears that the TH4 fabric does in fact breathe, but it may not be
> able to keep up with perspiration under conditions of heavy exertion (or
> people who sweat heavily).
I'm not sure that there's any "breathable" fabric that's able to keep
up with perspiration under heavy exertion.
In the first place, waterproof/breathable fabrics aren't supposed to
keep up with perspiration at all; they're supposed to pass ONLY water
*vapor.* If you sweat, or if the exterior is wetted out, that water
blocks the "pores" that pass water vapor anyway. The stuff doesn't
wick, which is what I think some folks expect of it. And even if it did,
it's a membrane (or a porous coating) and doesn't pass moisture
unidirectionally -- it will pass it equally in both directions. In other
words, if it COULD move sweat, it could also move rain. IN, toward you.
Which would not keep you dry.
The closest I've seen to unidirectional wicking is the Parameta S
material on my Paramo Mountain Shirt. But that's not waterproof (though
it is water resistant, at least in light precipitation).
The underarm zippers do an admirable job of
> controlling the comfort level during walking, and should be able to cool
> down overheated hikers with judicious use. I did note a couple of
> problems - with the hood alone, when I turned my head, the hood did not
> turn as well. If I tried to cinch it down more closely, I ended up
> covering my face. Closing up a sleeping bag hood until only your nose
> sticks out is fine while sleeping, but is not very useful in a jacket
> when walking. Adding my hat solved my dilemma, however.
Most hiking or mountaineering rain gear is designed to be used with a
hat or a climbing helmet, just as most bicycling rain gear is designed
to be used with a bicycling helmet.
I don't know about your parka, but I think my Thunderlight Jacket hood
has a cord with a cordlock in the BACK of the hood that will reduce the
volume of the hood to more closely fit the head. I could be mistaking it
for another jacket, so I'll check.