I disagree. If your sat in a room at say 10c with thermal underwear, thick socks, long Johns, hat, 3 jumpers, coat and thick hat and gloves. Then you'll probably be sweating, blood will be flowing inorder to get rid of heat.
Extra clothing lowers the temp at which blood flow to the extremities reduces. There isn't some arbitrary line at which no amount of extra clothing will make no difference, else you could say the same thing about house insulation. Is blood flow going to reduce just because it's 10c outside, regardless of the inside temp?
So you could still lower your thermostat significantly.
Plus dressing warmer could prevent this?!?