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Out-of-whack sleep habits can cause diabetes

 By Robert Bazell
Chief Science and Medical Correspondent
NBC News

How hard is shift work on a worker's body? 

Research out Wednesday from Brigham and Women’s Hospital in Boston demonstrates very precisely the way fighting the body's natural sleep patterns can increase the risk of type 2 diabetes, the most common form of the disease.

More than 21 million Americans are “shift workers,” according to U.S. Census figures. That is, they labor during the hours that most of us set aside for rest or sleep, either all or part of the time. That number is increasing 3 percent a year because of the nature of our service economy and the need for ever more people to take whatever work they can.

The sleep research team at Brigham and Women’s, under the direction of Dr. Charles Czeisler, has spent decades documenting how shift work can lead to increased obesity, heart disease, diabetes and many other health problems. In this latest research in their sleep lab they show how one mechanism creates the risk.

Twenty-one healthy volunteers were subjected to varying hours of sleeping and waking, light and dark, all designed to disrupt the body’s natural internal clock (the circadian rhythm.)

Within a few days, when the subjects ate a normal meal, their bodies did not respond in a normal way.

“Glucose levels went much higher and stayed that way for several hours,” said neuroscientist Orfeu Buxton, Ph. D., the study's lead author. “This was because of decreased insulin released from the pancreas. Together these reflect an increased risk of diabetes.”

The stress was so severe that during the three-week experiment three of the healthy volunteers became pre-diabetic. Fortunately, after nine days of normal sleep and waking, all symptoms disappeared.

Still, the experiment clearly demonstrates that shift work can make people diabetic. For people who already have diabetes or are pre-diabetic, it can make the conditions worse.

The advice from the scientists for those who perform shift work -- either out of necessity or choice:

  • Try to make your daily clock as normal as possible.
  • Get good sleep during the day -- finding, if you can, a quiet, very dark room. 
  • Don’t eat big meals at a time when you feel your body clock is out of whack.

Sound advice, experts would agree.  But anyone who works odd hours knows how challenging such simple routines can be in the demands of a normal family and social life. This latest research is further evidence out-of-whack sleep’s harm to our health.

The research is published in Science Translational Medicine.  You can read an abstract here: 

http://stm.sciencemag.org/lookup/doi/10.1126/scitranslmed.3003200

 Robert Bazell is NBC's chief science and medical correspondent. Follow him on Facebook and on Twitter @RobertBazellNBC

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