I don’t think breathing cold air during exertion is really good for your heart.
Then a lot of people I know should be dead right now.
My first memory, as a kid was waking up and seeing a glass bottle of milk on the kitchen table with the top popped off, and the milk frozen in an upside down "J" shape.
Years later, my parents told me I had been sleeping in the hottest room in the house. It was 42 below zero in the kitchen that morning.
No worries about pipes freezing.. There weren't any.
We got water from the brook a hundred yards or so in back of the house after chopping a hole in the ice every day.
We were in an old logging camp building. You could see between the boards on the walls. No big deal.