Historical considerations
In his comments at the meeting, Muhammad Rishi, MBBS, the lead author of the AASM’s position statement, added that circadian misalignment – that “asynchrony between the internal and external clocks” – is associated in studies with an increased risk of obesity, metabolic syndrome, and depression.
But he also emphasized that the “historical evidence” against permanent DST is at least as strong as the medical evidence.
“The U.S. has gone on permanent daylight savings time several times in the past, most recently in the 1970s during the OPEC [oil embargo], and it was so unpopular,” said Dr. Rishi, of the department of pulmonology, critical care and sleep medicine at the Mayo Clinic Health System in Eau Claire, Wis. “England also did it in the 1960s and then abolished it, and most recently Russia did it ... it became so unpopular with increased depression and mood disorders that they abolished it.”
Rep. Ward said that China has offered a large natural experiment with its move decades ago from five time zones to one time zone – Beijing time. “I don’t think we’ve seen any sweeping changes in their health because they have one large time zone,” he said.
Dr. Klerman took issue, saying she “knows someone in China who is trying to get that data about health outcomes and is unable to get it.”
Arguments that DST saves energy hold little to no weight upon scrutiny of the data, Dr. Johnson said. Moreover, research other than oft-cited, older Department of Transportation studies suggests that “permanent DST is bad for energy and bad for the climate,” she said. “This really needs to be more fully evaluated by the government and others.”
Dr. Johnson said after the meeting that it’s important for experts from the energy and climate sectors, education, and medicine – including pediatrics, oncology, and other specialties with “a stake in this” – to come together and share information so “we won’t all be in our silos.” She and other sleep experts in the neurology field are planning to host a summit in 2022 to do just this.
Dr. Johnson and Kin Yuen, MD, of the Sleep Disorders Center at the University of California, San Francisco, both expressed concern at the meeting that adoption of permanent DST would negate the benefits of delayed school start times in middle and high school students.
There is some evidence that delayed start times have led to decreased tardiness and absences, Dr. Yuen said. To have the same impact with permanent DST, “instead of starting at 8:30 a.m., you’d have to start at 9:30,” Dr. Johnson added after the meeting.
The first discussion of DST at the SLEEP 2021 meeting was led by Erin E. Flynn-Evans, PhD, MPH, director of the Fatigue Countermeasures Laboratory at the National Aeronautics and Space Administration Ames Research Center. Dr. Yuen led a later second question-and-answer session. They and each of the eight participants reported that they had no relevant conflicts of interest.
Dr. Yuen and Dr. Flynn-Evans are both coauthors of the AASM’s position statement on DST. Dr. Klerman is a coauthor of the Society for Research on Biological Rhythms 2019 position paper on DST.
The AASM’s statement has been endorsed by 19 organizations, including the American College of Chest Physicians, the SRBR, the American Academy of Cardiovascular Sleep Medicine, the Society of Behavioral Sleep Medicine, the National PTA, and the American College of Occupational and Environmental Medicine.