Each year, the end of Daylight Saving Time—scheduled for Sunday, Nov. 6 this year—comes along to
ruin our lives make our mornings brighter and our afternoons and evenings darker. But as much as we might mourn the loss of sunny evening hours, the end of daylight saving time means a return to our bodies’ natural circadian rhythms, according to ABC News. And that can actually be good for us.
A 2007 study found that our bodies’ internal clocks, or circadian rhythms, never really adjust to daylight savings time (the practice of turning the clocks forward an hour in the spring and back an hour in the autumn). These rhythms are in tune with natural changes in sunlight throughout the year—and apparently, they’re not so easily tricked as we might like. Daylight saving time is, after all, a social construct. Till Roenneberg, a German chronobiology researcher, called the whole idea of setting the clocks forward and back an example of ‘human arrogance.’ ”When you change clocks to daylight saving time, you don’t change anything related to sun time,” Roenneberg said. “We forget that there is a biological clock that is as old as living organisms, a clock that cannot be fooled.”
Roenneberg led the 2007 study mentioned above, which looked at the sleep patterns of 55,000 people in Central Europe. They found that, on days off work, people’s sleep patterns were more in tune with the natural seasonal progression of daylight hours than our artificially induced daylight saving time conception of them. In a second study, Roenneberg’s team found that the timing of both sleep and peak activity levels easily adjusted to the end of daylight saving time in autumn, but not to its start in the spring.
“When we implement small changes into a biological system which by themselves seem trivial, their effects, when viewed in a broader context, may have a much larger impact than we had thought,” said Roenneberg. “It is much too early to say whether DST has a serious long-term impact on health, but our results indicate that we should consider this seriously and do a lot more research on the phenomenon.”
“While we generally think that the time changes enforced by the DST transitions are ‘only an hour’ … this seemingly small hour translates to a repeat of 10 weeks in the annual progression of the relationship between our sleep-wake cycle and dawn,” he added.
Other researchers have noted a spike in suicides and heart attacks corresponding with the beginning of daylight saving time.
The seven-month period of daylight saving time was first implemented in various countries during World Wars I and II as a means to save energy (more daylight hours in the evening equals less need to rely on electricity for lighting homes, folks hoped). Until 2007, it ran from April until mid-October in the U.S.; but four years ago, Congress adjusted the daylight saving time period so it started three weeks earlier, in March, and ended one week later, in November. The idea behind the switch was also energy savings.
This year, the official time change in the U.S. will occur in the early morning hours of Sunday, Nov. 6, when clocks will be set back at 2 a.m. to 1 a.m. Expect the sun to rise that morning around 6:30 instead of 7:30.