Hot water bottle in your bed

I have blocks of ice for feet and it’s hard to sleep if they’re not warm. In the winter I make a hot water bottle of near-boiling water and put it under the covers by my feet. The bottle is still warm in the morning! They’re also great to hug if you need your torso to be warmer. Better than an electric blanket. Get a rubber water bottle, not a plastic one, they last longer. Our ancestors were on to something here!