Why does shoveling trigger heart attacks? How can you avoid becoming a victim?
Shoveling snow is a nasty heart-attack trigger, especially for out-of-shape people, said Dr. Richard Nesto, chairman of the department of cardiovascular medicine at the Lahey Clinic in Burlington, Mass. In fact, it's much worse for sedentary types than other forms of abrupt physical activity, like suddenly going for a jog.
While jogging gradually raises heart rate and blood pressure, snow shoveling produces a rapid, very steep rise in both. Shoveling is an isometric exercise, like weight lifting, "and there is no form of activity more strenuous to the heart than that," Nesto said. "The stress on your heart can go from normal to wicked high in five seconds."
Cold is also a trigger, which is why some people who use snow blowers also have heart attacks, he added.
In a normal person with no blocked coronary arteries, cold dilates, rather than constricts, the arteries, noted Dr. Richard Lange, chief of clinical cardiology at Johns Hopkins Hospital. But in people with atherosclerosis, or plaque in the arteries, cold causes a constriction of the arteries, which places an extra burden on the heart. This can happen even if just part of the face is exposed to frigid air.
This constriction, plus the increases in heart rate and blood pressure, can cause "vulnerable" plaques in coronary artery walls to rupture, allowing blood clots to block the flow of blood to the heart, said Dr. Murray Mittleman, director of cardiovascular epidemiology at Beth Israel Deaconess Medical Center.
If that weren't bad enough, many people shovel in the morning, when heart attack risk is highest. And many shovel right after eating, which causes blood to flow to the digestive organs and away from other areas of the body --such as the heart.
How can you protect yourself? Do not shovel or use a snow blower without your doctor's OK if you have had a heart attack or cardiac procedure, such as bypass surgery, an angiogram or angioplasty.
Ditto if you are out of shape or have heart attack risk factors such as smoking, high blood pressure, high cholesterol or a family history of heart disease.
If you're shoveling and have chest pain, shortness of breath, nausea, vomiting or sweating, seek medical care immediately.
"Often these symptoms are ignored," said Lange. "These people die."
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