A Swedish study that tracked 283,014 heart attacks between 1998 and 2013 found that the highest risk for holiday-timed myocardial infarctions is on Christmas Eve, with data showing that the peak hour is 10 p.m.

The day comes with a 37% higher risk of a heart attack than the 16-year-long study’s control period and the peak hour was much later than the control period’s peak of early mornings.

One of the goals of the study was to find out if holidays and sporting events trigger heart attacks, so the researchers analyzed symptoms and documented them to the minute.

The study also showed that there was a higher risk on Christmas Day and New Year’s Day, but not New Year’s Eve. These increases in risk were often associated with patients older than 75 who had another pre-existing illness, including diabetes and coronary artery disease, the study found.

The study found no increase in heart attacks during sporting events.

Heart attack symptoms include chest pain, shortness of breath, sweating and nausea. Women, however, may experience different symptoms including abdominal pain, pain in one or both arms and unusual fatigue. Call 911 for immediate help if you or someone else experiences these symptoms, but keep in mind that female patients have a higher success rate when treated by a female doctor.