If you woke up feeling a little groggy this morning, you’re not alone. For years, researchers have been tracking the (damaging) ripple effects of moving our clocks ahead one hour in the spring.
- A Michigan study uncovered a 24 percent spike in heart attacks on the Monday after the switch to daylight saving time (DST).
- Finnish researchers reported that the overall rate of ischemic strokes jumped 8 percent in the first two days after the time switch.
- Another study of national health data revealed “that the sleep disruptions during the spring transition cause the suicide rate to rise by 6.25 percent and the death rate from suicide and substance abuse combined to increase by 6.59 percent.”
“We don’t really know exactly why there is an increase in heart attacks and strokes during the change to [DST],” University of Miami Leonard M. Miller School of Medicine hypertension specialist Maria Delgado-Lelievre, MD, conceded. “It’s likely connected with the disruption to the body’s internal clock, or its circadian rhythm.”
Other side effects include a short-term drop in productivity, lost sleep (obviously), and multiple neurological and mental health threats. Previously reported issues include:
- A 2017 study found that hospitals saw an 11 percent bump in patients reporting more depressive symptoms right after the fall time change.
- Suicides – especially among men – jump in the days after daylight saving time.
- Substance abuse also ticks up.
A Persistent Health Concern
At the risk of piling on, a new paper – appearing in the American Journal of Health Economics – claims that there’s roughly a 6 percent increase in the incidence of depression among people living on the eastern side of time zone borders where the sun sets later.
“We had done papers on noise pollution and light pollution, and asked ourselves what we wanted to write about next,” Lafayette College’s Charles A. Dana Professor of Economics Susan Averett said in a press release. “We started to think about daylight saving time and the link between daylight and mental health.”
Over the course of the multi-year study, which leveraged data from the U.S. Centers for Disease Control and Prevention (CDC), Averett and her colleagues examined naturally occurring variations in solar time alignment. The team compared mental health outcomes for individuals living near time-zone borders. They took a special interest in those living on the east sides of those zones. They’re the ones who end up with more evening sunlight than their west-side counterparts.
Those on the east side of a time-zone border experience a greater mismatch between solar time and clock time. And the researchers found that this leads to higher levels of depression – and less sleep. DST, the team argued, only makes this “circadian misalignment” worse. Evolution has trained the human body to align with the pattern of the sun. And messing with that natural balance can threaten our mental health and sleep quality, Averett said.
“In the paper, we talk about the costs of mental health, including lost work days, so it feeds into the economy in ways that you might not see at first glance,” she explained. “When you make the switch and spring forward, you lose sleep and don’t feel like yourself for a couple days, like the feeling of being jet lagged, until you get used to it.
Following Up
But this isn’t research for its own sake. Averett and her co-authors submitted an op-ed to multiple national media outlets, pushing for a permanent shift to standard time. States such as Arizona and Hawaii, for example, already abandoned the biannual time change.
“As policymakers consider whether to eliminate the twice-yearly clock changes, they must recognize that our internal clocks are set by the sun. Ignoring this natural connection has serious consequences for our society’s well-being,” they wrote. “It is time for our policies – and our clocks – to catch up with our biology. Making [DST] permanent requires new legislation, but fortunately, making standard time permanent doesn’t.”
Further Reading
Circadian Rhythms Influence Caloric Intake
