Bad night"s sleep can hamper body"s insulin use
A man sleeps while riding the subway in New York, April 20, 2009 file photo. Credit: Reuters/Lucas Jackson
Researchers said their findings suggest it may be no coincidence that while sleep duration has shortened in western societies in the past decade there has also been an increase in cases of "insulin resistance" and adult-onset diabetes.
"Our findings show a short night of sleep has more profound effects on metabolic regulation than previously appreciated," said Esther Donga, director of Leiden University Medical Center in the Netherlands, who led the study published on Wednesday.
Type 2 diabetes is caused by the body"s inability to adequately use insulin, a hormone produced by the pancreas, to control glucose sugar produced from food. Sugar levels rise and can damage the eyes, kidneys, nerves, heart and major arteries.
The disease, linked to poor diet and lack of exercise, is reaching epidemic levels. An estimated 180 million people now suffer from diabetes around the world.
Previous studies have found that several nights of poor sleep can result in impaired use of insulin, but Donga said this was the first study to examine the effects of only a single bad night"s sleep.
The Dutch scientists examined nine healthy people -- once after a night of eight hours sleep and once after a night of just four hours.
The findings, published in the Journal of Clinical Endocrinology & Metabolism (JCEM), showed that partial sleep restriction during a single night reduced some types of insulin sensitivity by 19 to 25 percent.
"Our data indicate that insulin sensitivity is not fixed in healthy (people), but depends on the duration of sleep in the preceding night," Donga wrote in the study.
"In fact it is tempting to speculate that the negative effects of multiple nights of shortened sleep on glucose tolerance can be reproduced, at least in part, by just one sleepless night."
A study by U.S. scientists published last year found that people who slept less than six hours a night were 4.5 times more likely to develop abnormal blood sugar readings in six years compared with those who slept longer.
Experts say adults typically need between seven and nine hours sleep a night.
Donga said further studies were needed to see whether ways of improving sleep duration could help stabilize glucose levels in patients with diabetes.