Short-term sleep deprivation reduces insulin sensitivity in peripheral tissue, including fat cells, possibly leading to type 2 diabetes mellitus (DM) or obesity, according to a study published in the American College of Physicians journal Annals of Internal Medicine.
Researchers evaluated 7 healthy, lean men and women aged 18 to 30 years in a sleep laboratory during 2 study periods. Patients underwent 4 nights of 8.5 hours of sleep and 4 nights of 4.5 hours of sleep. Patients’ physical activity and caloric intake were controlled strictly regardless of sleep duration. At the end of each study period, the researchers administered an intravenous glucose-tolerance test to measure total-body insulin sensitivity. They also performed a biopsy of abdominal fat cells to measure how the fat cells responded to insulin.
After 4 nights of restricted sleep, patients’ total-body insulin response decreased by an average of 16%. Insulin sensitivity of fat cells decreased by 30%. The reduction is akin to taking the fat cell functioning of a healthy person down to that of an obese person or a patient with DM, the researchers noted.
The clinical study is the first to examine the causal pathways by which reduced sleep duration may contribute directly to DM and obesity, according to the authors of an accompanying editorial. They suggested that the results point to a much wider influence of sleep on bodily functions, including metabolism, adipose tissue, and cardiovascular function.