If you get caught on the road during a winter storm, stay in the car. Don't seek shelter or a telephone unless you can see one close by. For heat, turn on the car engine for brief periods. To keep water pipes from freezing, wrap them in pipe insulation. During sustained cold periods, let each faucet drip a little to avoid freezing.
Cold weather puts a strain on the heart, even without exercise.
During the Blizzard of 1993, more people died from heart attacks brought on by overexertion than any other cause. Be careful when shoveling snow, pushing a car or other exertion.