Doctors have a warning for southwestern Connecticut cardiac patients ? wintry weather could create a perfect storm for a heart attack.

According to doctors, heart attacks occur more frequently in December and January. Dr. Steven Kunkes, of Fairfield-based Cardiac Specialists, says studies show the risk of a heart attack doubles when the temperature drops below 25 degrees.

Doctors say those at risk for heart attacks should avoid being out in the cold weather. They also say cardiac patients should not shovel.