An "insidious" misalignment is hiding in almost half of U.S. adults' sleep schedules — and researchers have termed it "social jet lag," The Wall Street Journal reported Nov. 8.
Forty-seven percent of U.S. adults experience at least one hour of social jet lag — a difference in their circadian rhythms and the times they are expected to socialize in spheres such as work or school — according to a recent study of about 9,000 adults, published in JAMA Network Open and cited by the Journal.
"One hour of social jet lag is like traveling one time zone without even traveling," or going through daylight-saving time, Susheel Patil, MD, PhD, director of sleep medicine at Ohio's University Hospitals system, told the Journal.
Social jet lag is measured by taking the difference between a person's sleep midpoint on work and non-work days, according to the Journal. Study participants reported an average of 7.5 hours of sleep on work days and 8.2 hours on non-work days, causing disruption to their circadian rhythms.
"Jet lag can have a much more dramatic effect on people acutely. You feel jet lag when you travel. Social jet lag is more insidious. It's often hiding in plain sight, though it may have an impact on our health," Aric Prather, PhD, a psychologist at the University of California San Francisco, told the Journal.
Even when someone gets the recommended amount of sleep, if they are experiencing social jet lag, they are prone to poor health outcomes. These include higher risk for depression, obesity, type 2 diabetes and cardiovascular disease, as well as a tendency toward poorer eating habits and academic performance.
In addition, 30 percent of study participants reported trouble sleeping, and one-fourth said they were tired during the day, the Journal reported.