In a Heartbeat: Effects of daylight saving time
On Saturday, clocks fall back an hour as part of daylight saving time. Daylight saving time, or DST, was created in the United States in 1918 to allow for more sunlit hours in the evening during months when the weather is warm. In the spring, we advance our clocks ahead one hour. In the fall, we move them back an hour. The annual practice always sparks debate over whether changing the clocks remains necessary. We asked Brant Hasler, assistant professor of psychiatry and psychology at the University of Pittsburgh, for his opinion.
Daylight saving time: Do we still need it?
This remains a topic of controversy, particularly in terms of the supposed benefits for energy consumption. My personal opinion is that we do not — an opinion based on both the health downsides and from living in Arizona, where they do not observe daylight saving time and do just fine — but there may well be considerations outside my expertise.
What impact does daylight saving time have on the body?
The human biological clock is primed to shift later for most people, which is why there tends to be less jet lag when traveling westward. For this reason, the start of daylight saving time in the spring is harder on the clock, and given that the biological clock influences nearly every tissue of the body, this can have a wide-ranging impact. But both transitions are associated with sleep disruptions for up to a week afterward. Furthermore, although the findings are somewhat mixed, multiple studies have found negative consequences such as increased traffic accidents, increased heart attacks and decreased test scores. The sleep loss and jet-lag effects are likely contributors to these consequences. Notably, such problems tend to be worse following the spring daylight saving time transition, but there is also an uptick in accidents following the fall daylight saving time transition ... apparently because folks stay up later, sometimes drinking, and then drive home in a sleepier and/or more intoxicated state.
What are some tips for making the transition with ease?
Our biological clocks evolved to make small daily changes — the changes in day length that naturally occur over the course of the year. Thus, slowly shifting one's schedule by 15 minutes per day starting several days before the daylight saving time transition should be easier than the abrupt one-hour transition. Also, people who are natural night owls tend to have particular trouble adapting to the spring daylight saving time, mainly because daylight saving time prioritizes evening light over the morning light night owls need to keep their internal clocks synchronized to the outside world. The use of bright light in the morning and/or keeping lights dimmer in the evening might help night owls make an easier transition during the spring daylight saving time. Finally, with regard to the fall daylight saving time, if folks want to take advantage of the “extra hour” on Saturday night for more socializing and/or drinking, they should make sure they have a safe transportation option.