Hebdomadal rhythms of the heart

Why do deaths peak at the start of the week? Because we don't like Mondays

Dean Swift, in caustic vein, dubbed Monday the parson's holiday. But it certainly isn't a day of rest for the medical profession. The results of several recent studies warn that cardiologists in particular are likely to have a busy time.1-3 One study from Scotland by Evans and colleagues, published in the BMJ earlier this year, showed that in men and women under 50, mortality from coronary heart disease was about 20% higher on Mondays than on other days of the week.4 From North America, another study, which investigated a series of patients who had received implantable defibrillators with event recorders, showed that there was a clear peak in the occurrence of life threatening ventricular arrhythmias on Mondays.5

That fluctuations in rates of heart disease are linked to time is hardly news. It has been known for awhile that coronary events are two or three times more common in the early morning than during the rest of the day,6 and that both north and south of the equator there is a winter peak and a summer trough.7 This isn't really very surprising. Apart …