This sleep trick may be the most important for a long life
If you’re only going to change your sleep habits in just one way, set aside the advice that you need to get eight hours of sleep a night.
While getting enough sleep has proven health benefits, the more powerful predictor of longevity seems to be something else entirely, according to new sleep research.
Consistency — going to sleep and waking up at roughly the same time each day — is a stronger factor in securing a long life, according to a recent study in the journal Sleep.
The study finds that “sleep-wake timing can be a stronger predictor for some health outcomes than sleep duration.”
The findings, courtesy of researchers in Australia, the United States and England, join what we already know about sleep from a great deal of worldwide research. Previous research has shown that consistently sleeping too short or too long is associated with dying prematurely.
Studies have also shown that people generally need at least a certain amount of sleep, for adults typically around seven to eight hours a night. That number varies with age: Little kids and teens need much more. Older adults seem to require somewhat less.
According to the new research, getting six hours of sleep a night on a relatively stable schedule likely puts you in better shape than someone who gets eight hours but starts and stops their sleep on an erratic schedule.
The Wall Street Journal said the finding provides “hope for those of us who live (and sleep) in the real world: Getting less than eight hours of shut-eye a night doesn’t mean you’re doomed to an early grave.”
“We’ve been missing maybe half of the story,” Matt Walker, a neuroscientist and director of the Center for Human Sleep Science at the University of California, Berkeley, who wasn’t involved with the study, told the Journal. “Not just how much you sleep but the regularity with which you sleep has now come onto the map and exploded as perhaps the more important thing.”
The researchers write that “sleep regularity may be a simple, effective target for improving general health and survival.”
Sleep consistency and death
The recent sleep study involved 60,977 UK Biobank participants, average age just under 63 years old. Within not quite eight years, 1,859 had died. The researchers found that higher sleep regularity was associated with a 20-48% lower risk of all-cause mortality, 16-39% lower risk of cancer mortality and a 22-57% lower risk of cardiometabolic mortality, which includes such things as Type 2 diabetes, inflammation or obesity-related complications.
Unlike sleep regularity, sleep duration did not impact cancer deaths.
The Centers for Disease Control and Prevention says at least a third of Americans don’t get the amount of sleep recommended by health experts. CDC also says the risks from inadequate sleep include developing such chronic diseases and conditions as Type 2 diabetes, cardiovascular disease, obesity and depression. The public health giant notes barriers to high-quality sleep, including inconsistent sleep and wake times, interrupted sleep and napping.
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That’s not to say that sleep length doesn’t matter. Angus Burns, study co-author and research fellow at Harvard Medical School, told The Wall Street Journal that people who got long, consistent sleep had the least mortality risk, but that those who get shorter regular sleep had less mortality risk than those who sleep longer hours, but less consistently in terms of their sleep patterns. He suggested that if life interferes with getting long enough sleep, at least focus on consistency.
Burns said people should try to keep their sleep and wake times consistent without varying the window more than an hour or two.
What experts agree on
The National Sleep Foundation in September issued a new guideline created by a panel of sleep experts that emphasizes the benefit of consistent sleep schedules on health and performance. It was published in Sleep Health, the foundation’s journal.
The multidisciplinary panel said inconsistent sleep schedules have been linked to negative health outcomes, including diabetes, obesity, heart disease, immune system dysfunction, cancer and mental health challenges. They also said that sleeping an extra hour or two to catch up on sleep on non-work days if you’ve been shorted on sleep a bit “can benefit most people as a method to help recover from sleep debt.”
Consistent sleep is not just important to avoid bad outcomes, but to achieve good ones, “including alertness, cardiovascular and metabolic health, inflammation and mental health,” said the panel chair and senior author of the consensus report, Dr. Charles A. Czeisler, division chief of sleep and circadian disorders at Brigham and Women’s Hospital, and Frank Baldino Jr., a professor of sleep medicine at Harvard Medical School.
