FRIDAY, Nov. 28, 2003 (HealthDayNews) -- As winter temperatures settle in each year, emergency rooms see an upsurge of men complaining of chest pain.
The explanation has long been that these heart attacks are triggered by the unfamiliar physical exertion of shoveling snow or the sudden shock of colder temperatures.
However, there's ample evidence that heart attacks also increase during the winter in "sunbelt" states such as Florida and California.
So, what's the connection?
Scientists now think that inactivity may be at least partially responsible. A 1997 study by the U.S. Centers for Disease Control and Prevention found Americans are less active in wintertime all across the country. About one in three persons engaged in no physical activity whatsoever in January -- a peak of inactivity that coincides neatly with the observed increase in heart attacks.
Holiday stress and less sunlight may also be involved. Both trigger depression in some people, which can induce a heart attack.
Dr. Roy Ziegelstein, a cardiologist at Johns Hopkins University in Baltimore, discovered depressed people who have a cardiovascular disease are less likely to follow their doctor's recommendations to adopt a heart-healthy lifestyle -- including a low-fat diet, routine exercise, no smoking, stress reduction and regular socializing.
Another Hopkins researcher, Diane Becker, of the Center for Health Promotion, found people who overreact to stressful situations are more prone to constriction of their heart arteries. She believes this may put them at a higher risk of having a heart attack during physical activity, whether it's snow shoveling or carrying heavy suitcases during the holidays.
Dr. Thomas H. Lee, a cardiologist at Harvard University's School of Medicine, did find cold plays a role in some heart problems. Noting that cold temperatures can cause coronary arteries to squeeze down, Lee said this constriction would not be a problem for most people. However, for someone with atherosclerotic plaque, the narrowing could lead to chest pain or a heart attack.
He said a 30 percent blockage, which would not usually cause chest discomfort, could become a 70 percent blockage in very cold weather. Combining that with sudden physical stress could bring on the classic winter heart attack.
Learn more about the warning signs of a heart attack and stroke from the American Heart Association.