Simply being in the cold makes the heart work harder.
Shoveling snow may seem like a simple (albeit annoying) task, but it takes much more energy than you might think. The shoveling itself is tough work, but the added cold on your cardiovascular system demands a surprising amount of energy. For most people, this results in an excellent workout—but if you have a heart problem, it could result in an actual emergency.
Whenever you’re exerting yourself (whether at the gym or on the sidewalk), your myocardial oxygen demand increases—that is, the amount of oxygen your heart needs to fuel the body optimally. A few things have to happen for this to work successfully:
You pant, allowing your lungs to increase the body’s supply of oxygen.
The heart picks up the pace, working harder to send oxygenated blood throughout the body.
Your blood vessels expand, allowing a higher volume of oxygenated blood to pass through.
If you have a heart problem, these mechanisms can pose a challenge for you. For example, for people with atherosclerosis (a state of narrowed and less flexible blood vessels), the heart has to work even harder since the blood vessels are less able to expand.
Exercise gets even harder in the cold, since blood vessels naturally constrict when the body is chilly. Your blood vessels tighten up away from the skin’s surface in order to reduce heat loss. This causes goosebumps—as well as reduced blood flow.
When you put all these factors together, the combination of inflexible arteries, constricted blood vessels, and a fast-pumping heart can increase the risk of a heart attack.
How to Manage Your Risk
Despite all of this, avoiding exercise altogether is *not* recommended for people with heart problems. Physical activity can help manage the condition and reduce your risk of a heart attack, as long as it’s done carefully and safely. (Learn more about exercising with a heart condition here.)
Need to shovel? Here are tips to shovel safely in the cold if you have a heart condition:
Take frequent breaks while shoveling. Give your body a chance to replenish its oxygen supply and get the heart rate back to normal.
Avoid alcohol right before and after shoveling. (Don’t bother drinking whiskey to help you warm up—that’s a common myth about alcohol.)
Dress appropriately to reduce heat loss. A hat, gloves, scarf, and many warm layers are important. The warmth may help those blood vessels relax, despite the cold air.
Know the heart attack warning signs and be mindful and aware of how your body is feeling. Don’t “push through” potential symptoms. If you notice chest pain or pressure, or shortness of breath, stop immediately and get help.
If you have concerns about your health and the cold, talk to your doctor. Treating your heart problem (such as hypertension or high cholesterol) may help lower your risk of a heart attack, regardless of the weather.
Avoiding winter heart attacks. Cambridge, MA: Harvard Health Publishing, Harvard Medical School, 2016. (Accessed on January 29, 2020 at https://www.health.harvard.edu/heart-health/avoiding-winter-heart-attacks.)
Boyette LC, Manna B. Physiology, myocardial oxygen demand. Treasure Island, FL: StatPearls Publishing, 2020.
Cold weather and cardiovascular disease. Dallas, TX; American Heart Association, 2015. (Accessed on January 29, 2020 at https://www.heart.org/en/health-topics/consumer-healthcare/what-is-cardiovascular-disease/cold-weather-and-cardiovascular-disease.)
Warning signs of a heart attack. Dallas, TX: American Heart Association, 2016. (Accessed on January 29, 2020 at https://www.heart.org/en/health-topics/heart-attack/warning-signs-of-a-heart-attack.)