Heart attacks are most likely to occur on Mondays. The accepted explanation is that because Monday is the first day of the workweek, people feel more stress on Mondays than on other days. However, research shows that even unemployed retired people are more likely to have heart attacks on Mondays than on other days.
The statement 'Many retired people take up part-time jobs after they retire from their careers' most helps to explain the increased likelihood that an unemployed retiree will have a heart attack on a Monday.