Quote Originally Posted by yvette123 View Post
Well, generating enough body heat is not the big problem.
I honestly can't imagine why generating body heat shouldn't be enough. How cold do you mean? I bike down to -15 deg C and XC ski below that, and the problem is keeping dry, because you can't help generating excess heat if you're working hard enough to call it training. Feet can get cold if constricted in biking shoes, but that's a bit different, and I still would rather reckon on good insulation than a dodgy battery pack.