As pit said, human heat pads these days have an unbelievable amount of control systems to prevent overheating. I just took the temp of the one o have for my back on the low setting, barely got past 80. Now a days they have to take into account the moron factor for most of the country, and install redundant controls to prevent people from being stupid and hurting themselves.

i was just suggesting some kind of supplemental heat, but definitely isn't necessary