Lack of Deep Sleep Possible Cause of Type 2 Diabetes

Originally Written: 2008
Updated: April 2018

Poor sleeping habits are known to decrease the bodies ability to manage blood sugars, increasing the risk of obesity and subsequently diabetes. A 2007 study at the University of Chicago found a direct connection between insufficient non-rapid eye movement (NREM) sleep, also known as slow-wave sleep (SWS), and type 2 diabetes. This was the first study of its kind.

The study focused on young adults in their twenties and early thirties, who are known to average between 80-100 minutes of SWS per night (as opposed to approximately 20 minutes of SWS for an individual in their sixties – low levels of SWS are often associated with older and obese individuals, two groups at increased risk of contracting type 2 diabetes.). Five men and four women, in good health, and ranging in age from 20-31, participated in the study.

The participants were first observed for two nights of “normal,” uninterrupted sleep. This was followed by three nights of interrupted sleep, in which noises were sounded when the individuals were observed to be going into SWS. These noises were not at a level in which they awakened the participant, but kept them asleep and out of SWS.

As the nights of interrupted sleep progressed, more noises were necessary as the deprivation of SMS increased the need for SWS in the participants. By the third night, upwards of 300 noises were necessary to keep participants out of SWS. The total amount of sleep for each of the five nights was kept the same.

Following each nights sleep, participants were injected intravenously with a glucose solution, and their blood sugar and insulin response was measured.

Following the third night of interrupted sleep, insulin response was down 25% on average from that of uninterrupted nights of sleep. This decreased insulin response brought these normally healthy individuals to “the level reported for populations at high risk for diabetes,” the study suggests. Blood-glucose levels were also up an average of 23% following the third night of interrupted sleep, again to levels of high diabetes risk. “The magnitude of the decrease in insulin sensitivity was strongly correlated with the magnitude of the reduction in SWS,” says the study.

The study essentially turned the sleeping patterns of healthy young adults into those comparable to elderly and obese individuals, The observed decreased insulin response and increased blood-glucose levels were substantial, suggesting healthy, uninterrupted sleeping patterns are very important in preventing diabetes. As the study concludes:

“These findings demonstrate a clear role for SWS in the maintenance of normal glucose homeostasis [balanced blood-sugar levels]. Furthermore, our data suggest that reduced sleep quality with low levels of SWS, as occurs in aging and in many obese individuals, may contribute to increase the risk of type 2 diabetes.”

Original Source: Tasali, Esra. Leproult, Rachel. Ehrmann, David. Van Cauter, Eve. PNAS. “Slow-wave sleep and the risk of type 2 diabetes in humans.” December 2007.

Update: A 2015 comprehensive meta-analysis study of sleep as a risk factor for type 2 diabetes further confirmed that both too little and too much sleep increases risk, and emphasized the important role of “deep” short wave sleep in metabolic function.


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