Blood pressure generally is higher in the winter and lower in the summer. That's because low temperatures cause your blood vessels to narrow, which increases blood pressure because more pressure is needed to force blood through your narrowed veins and arteries.
Few people realize as the temperature drops, too much exertion can actually trigger a heart attack.
Cleveland Clinic cardiologist Dr. Leslie Cho says cold outdoor temperatures can cause arteries to constrict - and that can cause a sudden increase in blood pressure. She says the increase in blood pressure combined with too much physical exertion can be very dangerous.
"Shoveling snow is actually quite dangerous because it's actually a very heavy workload. So if you haven't been doing regular exercise and all of a sudden that first snowfall comes and you're shoveling a lot of snow out there it can create an excess burden," she explains.
Doctors often see an increase in heart attacks during the winter months.
"You have to take it easy. If you haven't done any exercise throughout the year, maybe this is not the time to shovel your entire driveway," she advises.
Before you go out, check your pulse rate, she says. Here's how.
"Count it out for 30 seconds, multiply it by two and go out and shovel," she says. Your pulse will quicken when shoveling. "Go back inside after 15 minutes and then return when your pulse is back to normal."
Cho says the best way to protect your heart during all seasons is to eat a healthy diet, get regular exercise and keep stress levels to a minimum.