21.05.12
So there's something about winter. But what?
"Nobody knows," says David Phillips , a sociologist at the University of California-San Diego who studies expiry patterns. Flu and pneumonia, which are tough on people with heart disease, evidently play roles in the high rate of all natural deaths in the winter, he says.
Shorter, darker days might consequence, too, says Kloner, who has studied the winter link.
But he is convinced that one big agent is cold itself — though the heart death spike shows up even in warmer states. "It's still colder in the winter," he says. "Even in Los Angeles, (in break of dawn December) the temperatures in the morning were in the 30s."
Cold alone, he says, can make blood vessels constrict, blood pressure get somewhere and the heart work harder. It also might trigger changes in the blood that construct clotting and inflammation.
Just walking outside and taking an icy gust can "create a crisis," says American Heart Association spokeswoman Tracy Stevens, a cardiologist at Saint Luke's Fitness System in Kansas City, Mo. "That sudden exposure can cause constriction of the coronary arteries or lung constriction, which creates shortness of whiff and puts a strain on the heart.
Source: USA TODAY