The sun will set today around 4:30 p.m. where I live in New York City, half an hour before you can respectably show up at happy hour. Maybe it’s because of the early darkness, or because the holidays are occasions to slow down and curl up. Maybe it’s because flu season gives people an easy excuse to dodge nighttime socializing and head home to bed. Whatever the reason, this is the time of year when even the most committed night owls seem to get to sleep a little earlier. Now, some new research shows that might be a good thing—not just for smoother, less grumpy mornings, but for physical and mental health.
The study, out of Binghamton University, found that people who sleep less, and those who go to bed later at night, are more likely to suffer from “repetitive negative thinking“—focusing on negative experiences in a cycle of thoughts they can’t control. These kinds of negative thought patterns are associated with anxiety disorders—PTSD, OCD, depression, and social anxiety disorder—but they’re not limited to people who have these disorders. Scientists have known for years that of the different “chronotypes”—basically, morning people and evening people—evening types are more likely to suffer from depression. The Binghamton study takes this knowledge a step further, showing the link between later bedtimes and excessive worry about the future, upset feelings about the past, and general intrusive thoughts.
Researchers Jacob Nota and Meredith Coles had 100 university students complete questionnaires and computerized tasks to measure how much they ruminate and worry. Both the night owls and the sleep-deprived were more likely to be plagued by these intrusive thoughts. The researchers noted that “making sure sleep is obtained during the right time of day may be an inexpensive and easily disseminable intervention.” Though they’re not sure of the mechanism that links bedtime and negative thinking, researchers think it could be that disrupted sleep may make the mind less able to fend off repeated unwanted thoughts, and that sleeping more and earlier could fix the problem. In other words, move over, talking cure; the sleeping cure has arrived.
A study analyzing 124,000 questionnaires about chronic sleep loss revealed that the main reason people lose sleep is work. This is true across all social and demographic groups.
Another recent study showed that going to sleep later at night can lead to late-night eating and weight gain. In a study conducted at the University of Pennsylvania’s Sleep and Chronobiology Laboratory, researchers studied 225 healthy, non-obese individuals. One group of subjects were put on a restricted sleep schedule—they slept only four hours a night, and went to bed at 4 a.m. Another group slept for a generous ten hours a night and went to bed at 10 p.m. Both groups ate meals at regularly scheduled times and had access to food and drink from the laboratory kitchen if they wanted to eat at other times. Both on days that they stayed up late and on days after they had stayed up late, members of the sleep-restricted group consumed an average of 500 extra calories and ended up gaining weight over the course of the two-week study.
Though going to bed early sounds like an easy cure-all, getting more sleep isn’t as easy as it sounds, as any frazzled coffee-addict knows. A study analyzing 124,000 questionnaires about chronic sleep loss revealed that the main reason people lose sleep is work. This is true across all social and demographic groups. The study’s lead author, Dr. Mathias Basner of the University of Pennsylvania School of Medicine, said there was overwhelming evidence that “time spent working was the most prominent sleep thief.” Work and lack of sleep were also correlated in a study of working mothers and their children, which showed that kids whose mothers work full-time get less sleep and have higher BMIs. Researchers posit what seems clear to anyone juggling the responsibilities of work and family: that there’s a tradeoff going on between work hours, home responsibilities, and sleep.
When there simply aren’t enough hours in the day, it can seem like a no-brainer to choose work or time with loved ones over getting enough sleep. Time spent sleeping can seem like time wasted, when you could otherwise be doing something useful. But maybe it’s time to rethink sleep: view it not as wasted time, not as a luxury item, but as one of the most productive things you’ll do all day.