Two nights of extra sleep reverse sleep-loss diabetes markers

Two nights of catching up on sleep after a series of nights with sleep restriction were able to reduce markers of diabetes risk in a group of healthy young lean men, according to the results of a study published recently in Diabetes Care.

Specifically, two nights of about 10 hours of sleep improved insulin sensitivity and restored disposition index-a marker of diabetes risk-to levels seen in these healthy men after a normal night’s sleep.

“We were not surprised that young healthy lean men can recover from four nights of sleep loss. What is important to note, however, is that this was only one cycle of sleep loss,” co-author Josiane L. Broussard, PhD, of the department of integrative physiology, University of Colorado Boulder, told Medical Economics. “It is not known if you could recover with extra sleep on the weekends if this cycle is repeated day-in and day-out.”

According to Broussard, sleep is an important topic to study because every organism needs sleep, yet
humans commonly curtail sleep in modern society.

“Sleep loss has been linked to an increased risk for many negative health outcomes and diseases,” she said.

Loss of sleep, or sleep restriction, is associated with insulin resistance and increased risk for type 2 diabetes. In this study, Broussard and colleagues investigated whether two nights of good sleep, or sleep recovery, similar to that which would occur on a weekend, could reverse the negative effects of short-term sleep restriction.

They enrolled 19 healthy young lean men with a mean age of 23.5 years and BMI between 19.0 and 24.9 kg/m². The men were studied them in a controlled laboratory during both normal sleep (8.5 hours in bed for four nights) and sleep restriction (4.5 hours for four nights). Immediately after, patients were allowed sleep recovery, defined as two consecutive nights, the first with 12 hours in bed and the second with 10 hours in bed. 

During the study, patients had intravenous glucose tolerance tests performed after the four nights of normal sleep, four nights of sleep restriction, and two nights of sleep recovery. These tests revealed a 23% reduction in insulin sensitivity after sleep restriction compared with after normal sleep. This improved after sleep recovery, the researchers wrote. In addition, sleep restriction reduced disposition index by 16% compared with normal sleep, consistent with increased diabetes risk. Disposition index reverted back to normal after the patients were able to get recovery sleep.

According to Broussard, it is not known if people could recover with extra sleep on the weekends if this cycle was repeated day in and day out. Also, an older population, or a population with obesity/diabetes may not be able to recover each week after only two nights of extra sleep.

“This is certainly not a ‘free pass’ to people to lose sleep during the week and assume they will recover on weekends. Getting enough sleep at all times is the goal, but when enough sleep is not possible, any
sleep extension you can get is better than no sleep,” Broussard said.