Killer Snow

Every winter, about 1,200 Americans die from a heart attack or some other cardiac event during or after a big snowstorm, and shoveling is often the precipitating event.

Why is shoveling so hazardous?

• Shoveling uses your shoulders and arms, and upper body exercise tends to put strain on the heart because those muscles aren't well conditioned.
• Working in an upright position adds to the arduousness because blood pools in the legs and feet, so to maintain blood pressure, your heart must work harder.
• Much of snow shoveling is isometric exercise: your muscles are working, but there's little actual movement until you finally heave a shovelful up on the bank. During isometric exercise of any type, your heart rate goes up, and your blood vessels constrict, presumably to send more blood to the straining muscles. As a result, your blood pressure goes up.
• Without knowing it, shovelers sometimes perform a version of the Valsalva maneuver, bearing down as they would during a bowel movement while holding their breath. Waiting to exhale while straining like that can lead to abrupt changes in your heartbeat and blood pressure.
• First thing in the morning, the time when many people dig out from a storm, stress hormone levels tend to be higher, platelets in the blood "stickier," and heart attacks more likely.
• Shoveling involves exposure to the cold, another cardiac stressor.
• People who are out of shape often shovel, making the sudden intense exercise even harder on the heart.
• Most people don't warm up before they shovel or cool down afterward.

If you have a heart condition, you shouldn't shovel under any circumstances. People older than 50 should also try to avoid it. Contact your local council on aging to see if they provide a list of teens in your neighborhood who you can hire to do the job for you. Or buy a snow blower. If you must shovel, take it easy. Rest often. Dress warmly and stay well hydrated. Wherever possible, push the snow rather than lift it. Clear only the snow that blocks your path into the house, the rest will melt on its own. And of course, listen to your body. Head home if you experience potential signs of heart trouble, including chest pain, palpitations, undue shortness of breath, fatigue, lightheadedness, or nausea. Also stop if your fingers or toes get numb or hurt — you could have frostbite.

January 2003 Update