The American Heart Association is warning that clearing snow can pose serious health risks, especially in cold weather and rural areas where emergency response times may be longer.

Research shows that the heavy exertion of shoveling snow can sharply increase the risk of heart attack or sudden cardiac arrest — even in people with no known heart disease. The strain of lifting heavy, wet snow, combined with cold air tightening blood vessels, can push the heart to dangerous levels, experts say.

“Shoveling can be as demanding as a treadmill stress test,” said Dr. Larry Markham, president of the AHA’s Indianapolis board. “For people who are out of shape or already have risk factors, it can be a perfect storm.”

The AHA says shoveling snow relies heavily on arm strength, which puts more stress on the heart than leg-heavy activities. Many people also hold their breath while lifting, causing heart rate and blood pressure to spike. Cold temperatures further constrict blood vessels, increasing the strain.

People with a history of heart attack or stroke, or those with diabetes, high blood pressure, high cholesterol, obesity, or a sedentary lifestyle are urged not to shovel snow at all.

For those who must shovel, officials recommend taking it slow, dressing warmly, covering your mouth and nose, and pushing snow instead of lifting it. Using a snow blower can reduce physical strain but still requires caution.

Anyone experiencing chest pain, dizziness, or irregular heartbeats should stop immediately and call 911 if symptoms persist. If someone collapses while shoveling, bystanders should call for help and begin Hands-Only CPR.

More safety information is available at www.heart.org.