Do you really lose most of your body heat through your head?
What's less certain is how to stay warm. We've probably all been told to put on a hat when we step outside on a day like this -- we're told a large percentage, somewhere between 40-80% of our body heat, is lost through the top of our head. But is that true?
We called up Ollie Jay for the answer. He's a professor at the University of Ottawa who studies human survival in extreme environments.
Photo by Jeff McIntosh/Canadian Press