However, “it was not clear whether glucose intolerance was due to the changes in food intake or energy expenditure or to the sleep deprivation itself,” explained a team of researchers from Toho University in Japan.

In the study done over mice, blood glucose levels were found significantly higher in the sleep deprivation group than controls after one six-hour session of wakefulness.

Triglyceride (fat) levels and the production of glucose in the liver also increased in the sleep deprivation group after a single wake period.
Elevated liver triglycerides are associated with insulin resistance, or the inability of the body to process insulin properly.

In addition, lack of sleep changed the expression of enzymes that regulate metabolism in the liver in the sleep deprivation group.

These findings suggest that “intervention studies designed to prevent sleep deprivation-induced hepatic steatosis and insulin resistance should be performed in the future,” the researchers noted.

For the study, published in the American Journal of Physiology-Endocrinology and Metabolism, the team examined two groups of mice. During the sleep/wake period, the animals also had limited opportunity for physical activity.

One group was kept awake for six hours each night (“sleep deprivation”), while the control group was allowed to sleep as desired.