Cold weather and hard work can mask those symptoms, delaying people's responses and sometimes leading them into more trouble.
"People can be quite short of breath and think it is just from the exertion of what they're doing. Some people could neglect to notice the arm pain [of a heart attack]," said McBride.
"We really encourage people beyond the age of 50 to try to hire a neighborhood kid to do it," he added.
Not everyone is at risk for a heart attack while shoveling, of course and people in cold climates often have "conditioning," according to Dr. Randal Thomas, director of the Mayo Cardiovascular Health Clinic in Rochester, Minn.
But Thomas worried about people in the areas hardest hit now -- areas that usually shut down after a few inches of snow.
"Snow shoveling is probably not a good first-time exercise for people who are sedentary or overweight," said Thomas, who recommended people take breaks while shoveling and try to push the snow as far as possible before lifting it.
"If they develop acute symptoms while shoveling, they should stop shoveling first and sit down and rest inside," said Thomas. "If they continue to have chest tightness or severe shortness of breath after five minutes, they should go ahead and call 911."