Daylight-Saving Is Not Heart-Saving Time

Daylight-saving time, which means turning the clock forward one hour in the spring and one hour backwards in the fall, interferes with the duration and quality of sleep at each shift. Swedish scientists have now examined the influence of daylight saving shifts on the occurrence of heart attacks; they have described their findings in a letter to the New England Journal of Medicine.

Using data from the Swedish registry of acute myocardial infarction, they found that the incidence of heart attack was significantly increased on the first 3 weekdays after the shift to daylight saving time in the spring; and, in the fall, there was a decrease in the rate of heart attack on the first day after the return shift to normal time.

The researchers find that the most plausible explanation for these findings is the adverse effect of sleep deprivation on heart health. Of course, there is a well-known increased risk of heart attack on Mondays. This is why the comparisons were made to the average rates on the same weekdays before and after the shift days over the previous 15 years.

If daylight saving is indeed unhealthy, what's to be done? Just turn over and sleep for an extra hour or so - and tell the boss you overslept.