Don't know what is up with Jonnythan. I guess he's never seen real cold or snow. He should try making a trek up to the Canuckistan Prairies, where winter air temperatures frequently reach beyond -76F with the windchill.
Maybe us Canucks are just more hardy, or maybe we just happen to know a thing or two about dressing warm and staying warm while exerting ourselves during our cold winters.
I do know that the Helly-Hansen sells some of the best coldweather gear on the market, and usually exceeds some of the toughest standards around. SARC, Military, and other such organizations use their thermalwear worldwide. Nevermind the huge saturation of their wares into mountaineering, skiing, and other coldweather sports.
Can that many people be wrong about their thermal properties?
Helly-Hansen Workwear