Dec. 16--When temperatures dip during cold snaps, your body notices.
And it's not just your fingers and toes. Recent research shows that the risk of heart attack rises whenever the temperatures drop.
In a study of hospital admissions in England and Wales, British researchers found that for every one-degree Celsius the temperature dropped in a day, an extra 200 heart attacks were reported at hospitals.
Using that data, researchers calculated that the risk for heart attack increased by two percent for every degree the temperature fell. The results were adjusted to take into account other factors that might influence the heart attack rate, including air pollution and flu activity.
If cold weather brings on more heart attacks, what is cold enough to induce more heart attacks? In the British study, a majority of the heart attacks occurred when the temperature reached 53 degrees Fahrenheit (12 degrees Celsius) or colder.
The study doesn't explain why this happens, but doctors know that when the temperatures are colder, your blood is more likely to clot and there's a change in the thickness of blood. Also, blood vessels narrow in cold temperatures -- and that could raise blood pressure because more pressure is needed to move blood through those narrowed vessels.
In the Mount Sinai School of Medicine's Focus on Healthy Aging newsletter, cardiologist Bruce Darrow notes that cold weather brings on other changes in the body -- for instance, your body reduces blood flow to your extremities (fingers and toes) in cold weather. In addition, cold temperatures may affect the body's production of hormones that regulate blood pressure.
In the British study, people ages 75 and older appeared to be at higher risk for heart attacks during cold weather, as were those who already had been diagnosed with heart disease or other heart risk factors, including high blood pressure.
People who were taking aspirin daily appeared to have a lower risk for heart attack in cold weather than those who didn't take aspirin.
Because doctors aren't entirely sure what causes the increase in heart attacks, it's difficult to give concrete advice to patients. But they do make these suggestions:
--Limit your exposure to cold weather and the time you spend doing strenuous activities, including shoveling show, yard work or exercise.
--Wear layered clothes that will keep you warm; be sure to wear a hat and gloves or mittens because heat can escape the body through the extremities.
--Keep your home warm in the winter and consider adding insulation or taking other steps to maintain a comfortable temperature inside.
-----
To see more of The Orlando Sentinel or to subscribe to the newspaper, go to http://www.OrlandoSentinel.com.
Copyright (c) 2010, The Orlando Sentinel, Fla.
Distributed by McClatchy-Tribune Information Services.
For more information about the content services offered by McClatchy-Tribune Information Services (MCT), visit www.mctinfoservices.com.