Are you catching your ZZZZs? Researchers at Boston's Brigham and… (Myung J. Chun/Los Angeles…)
Too little sleep — or disrupted sleep — seems to increase the risk of diabetes and obesity, scientists found during a recent lab experiment.
Orfeu Buxton, a neuroscientist and sleep researcher at Brigham and Women’s Hospital in Boston, placed 21 test subjects in isolation for nearly six weeks. For the three weeks before the experiment began, he and his colleagues instructed the volunteers to spend 10 hours in bed, to make sure they got an optimal level of sleep.
Then the subjects moved into dimly lit, isolated suites in the laboratory, where the research team removed "time cues" and otherwise disrupted the volunteers’ sleep, allowing them only about five hours of per 28-hour period, scattered over various times of the day and the night. Participants were not allowed visitors or Internet access. One person came in with 20 years’ worth of photo-stuffed boxes and came out with well-organized photo albums, Buxton said. Another wrote a long paper.
During the experiment and after a recovery period, Buxton and his team measured resting metabolic rates and insulin and glucose levels. On average, pancreatic insulin secretion dropped about a third from where it should have been, increasing glucose levels after meals as a result. Three subjects hit “clinically relevant” prediabetic glucose levels, Buxton said.
The researchers observed an 8% decline in resting metabolic rate among the subjects when their sleep was bad. “That might sound like a small number, but it’s enough where you would gain 10 to 12 pounds in a year,” Buxton added. “Within three or four years, you could be obese.”
Once allowed to sleep normally again for nine nights, the subjects recovered. To the researchers’ surprise, there did not seem to be significant differences between responses of the younger study participants (a group of 12 people whose average age was 23) and the older study participants (12 people whose average age was 60), Buxton said.
The findings have important ramifications for public health in the U.S. While associated with folks who work on rotating shifts, poor sleep affects others as well — including those of us who work hard all week and attempt to “catch up” by sleeping in over the weekends (a phenomenon Buxton calls “social jet lag”). According to this sleep map on the Centers for Disease Control and Prevention's website, the highest reports of persistent insufficient sleep are in the Southeast.
“That map exactly matches stroke and heart disease and poverty and diabetes,” Buxton said.
To reverse the ill effects, he recommends everyone get between seven and nine hours every night — “8.5 is the new eight,” he advised.
Turn off ringers. Don’t eat at night. Sleep in a cool, dark, quiet room. And stop playing with your iPhone. “The Internet and all these devices clamoring for our attention aren’t making it any better, ” Buxton said.
The research was published Wednesday in the journal Science Translational Medicine (subscription required.)