Winter is bad for those with heart disease, but Christmas Day and New Year's Day are the worst.

Several studies show there is often a spike in deaths from heart disease on those two holidays.

The spike may be attributed to lifestyle habits during the cold months. This is when many people eat too much, drink too much, smoke too much and exercise too little.

It's because of those factors, when people with heart disease are faced with shoveling heavy snow, a heart attack can be triggered. "Buildup of plaques and cholesterol in the blood vessels, the plaques open, then they clot and that causes the heart attack or stroke," says Dr. Norm Campbell from the University of Calgary.

Dr. Campbell says getting to the hospital quickly after the first sign of a heart attack or stroke is crucial because there are treatments that can prevent lasting damage. Even that is a more difficult thing at this time of year because many people attribute their symptoms to indigestion from too many holiday treats.