> I'm not sure about it stopping you sweating? The article I read said if your temperature was ok, it would stop you producing the sweat you need to keep your sking moist, once a certain level was achieved.
I don't think it stops you sweating directly. I think it helps keep you from losing heat by evaporation. And ...
> If you are hot in a VB, surely you would sweat like hell?
Precisely. Sleeping cool is advised.
> If you are in a damp but not cold (i.e above freezing) climate and you generally have no problem with moisture in your insulation, would a VB still improve the insulation or just help by reducing the evaporative heat loss?
Stephenson advocates wearing VB clothing under warmer conditions than most would (could?) tolerate. Few agree with him, afaik.
> Is VB really just for sub-zero use.
I think it is often suggested for below ABOUT -10 C, but I haven't seen many suggest it for much warmer than that. However, doubtless some use it under warmer conditions - it might depend on the individual and how much he sweats.