Blue Monday, that post-weekend, down-in-the-dumps day, may indeed be dangerous to your health. More men die suddenly of heart disease on Monday than on any other day of the week, reports a group of University of Manitoba researchers in the Journal of the American Medical Association. Your heart also knows about TGIF (Thank God It's Friday), because that's the workday when the fewest men die of heart attacks. A long-term follow-up study of nearly 4,000 men found that 38 had died of sudden heart attacks on Monday while only 15 died on Friday. For men with no history of heart disease, Monday was particularly dangerous. Among that group, an average of 8.2 heart attack deaths occurred on each of the other six days of the week, while nearly three times as many occurred on Monday.

"Psychological stress has been related to sudden cardiac death, and it may be that return to work serves as a stressor," says Dr. Simon W. Rabkin, one of the researchers. But being at home on Blue Monday didn't help much either, since 46.7 percent of the fatal heart attacks occurring in the home also happened on Monday. "The warning 'Beware of Mondays' should be stimulus for further research to determine why," Rabkin adds.