'Tis the season—for heart attacks? Not to dampen any spirits, but studies show heart troubles spike this time of year.

It's not just a Western phenomenon; recent research in China found the same thing. The increase includes fatal and nonfatal heart attacks and a less serious condition dubbed "holiday heart syndrome," which is an caused by too much booze.

Reasons for the seasonal increase are uncertain. Theories include cold weather, overindulgence and stress.

American Heart Association spokesman Dr. Richard Stein, a cardiologist at New York University's medical center, says most studies investigating holiday heart trends have found a statistical increase in heart attacks and other problems. It's not a giant surge but worth noting just the same.

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