Lack of sleep or erratic slumber from working late-night shifts or travel may lead to diabetes and obesity, according to a Harvard University study that is the first to tie abnormal sleep patterns to disease.
In a trial of 21 men and women observed in a sleep laboratory, those allowed only 5.6 hours of sleep in a 24-hour period over three weeks had a slowdown in their metabolism and a reduction in insulin production. Those changes can lead to weight gain and increased blood sugar, according to research published Wednesday in the journal Science Translational Medicine.
Sleeping, eating and being active at times that are at odds with the body's internal clock, called circadian disruption, may raise the risk of diabetes and obesity as metabolic changes occur, said Orfeu Buxton, the lead study author. More research is needed to understand the results, he said.
"We disrupted not just the timing of sleep but the timing of meals, so it seems that eating meals at an unusual time may also play a role," said Buxton, as assistant professor at Harvard Medical School and an associate neuroscientist at Brigham and Women's Hospital in Boston.
Allowing workers to stay on the same shifts for longer periods rather than changing every few days may help them stave off health problems, Buxton said.
The sleep allowed in the study occurred at all times of the day and night to help copy the schedule of rotating shift workers. Chronic sleep restriction and disruption to the body's internal clock caused about a one-third decrease in insulin secretion after a standard meal, the researchers found. Too little insulin raises glucose levels in the body for longer periods and may increase the risk of diabetes, Buxton said.
Participants also experienced an 8 percent drop in resting metabolism, the amount of calories burned by the body's muscle excluding exercise. The slowed metabolism could contribute to a 12.5-pound increase in weight over a year.