How Sleeping Poorly Can Increase the Risk of Diabetes

University of Chicago researchers have reported a small study that suggests that reduced sleep duration, even when artificial, can result in metabolic changes usually associated with type 2 diabetes. It’s reported in the Journal of Clinical Endocrinology and Metabolism.

Observational reports indicate that shortened sleep is associated with an increased incidence of diabetes. The researchers decided to look at how this might occur. They studied 11 healthy volunteers (5 were women) with an average age of 39 and an average body mass index (BMI) of 26.5. The participants were subjected to two 14-day periods of controlled exposure to sedentary living with unlimited food; one period allowed 5½ hour, and the other 8½ hour bedtimes. Thus average sleep duration was reduced by just over 2 hours a day during the short bedtime period. The order of the periods was randomly assigned, i.e. this was a randomized crossover study. At the end of each period, oral and intravenous glucose challenge tests were done.

Both study periods were associated with comparable weight gain. Oral glucose tolerance was reduced (2-hour levels were 144 vs. 132 mg/dL) with the 5½- compared with the 8½ hour sleep period. Insulin sensitivities were also reduced with less sleep – 3.3 vs. 4.0 mUL/min for the two periods, respectively, as were measures of glucose effectiveness.

It must be noted that these subjects were not living a totally normal life during the study. They had restricted activity and unlimited food, both risk factors for the development of diabetes. However, the differences between the two periods were impressive, given the shortness of the periods. Lack of sleep – artificial or because of mental or physical problems – had clear-cut effects, all pointing in the same metabolic direction. Obviously, lack of sleep needs to be corrected, as far as possible. Similar studies should be done under other circumstances, e.g. in insomniacs, with and without a sedative.