Inadequate Sleep Raises Diabetes Risk in Women

Chronic insufficient sleep has been identified as a factor that can increase insulin resistance in otherwise healthy women, with more pronounced effects observed in postmenopausal women, according to a study funded by the National Institutes of Health (NIH). Published in Diabetes Care, the research underscores the critical role of adequate sleep in reducing the risk of type 2 diabetes, a condition where the body fails to effectively use insulin to maintain healthy blood sugar levels. 

Marishka Brown, Ph.D., director of the National Center on Sleep Disorder Research at the National Heart, Lung, and Blood Institute (NHLBI), emphasizes the significance of understanding how sleep disturbances impact the health of women, especially postmenopausal women, given that women generally report poorer sleep than men. 

The study focuses on the link between sleep duration and insulin resistance in women, particularly investigating the effects of prolonged, mild sleep restriction—a reduction of just 1.5 hours each night. Previous research has shown that sleep restriction can elevate the risk for various conditions such as cardiovascular disease, hypertension, and disordered glucose metabolism, leading to insulin resistance and type 2 diabetes.

However, many of these studies were conducted only in men or involved short-term, severe sleep restriction. The study enrolled 40 women aged 20-75 with healthy sleep patterns (7-9 hours per night), normal fasting glucose levels, but elevated risks for cardiometabolic disease due to factors like overweight or obesity, family history of type 2 diabetes, increased lipid levels in the blood, or cardiovascular disease. 

Participants wore wrist sensors to record their sleep patterns during a two-week baseline period. Subsequently, they completed two six-week study phases in a random order—one maintaining healthy sleep patterns and the other involving sleep restriction. Participants took a six-week break between the study phases.

The researchers performed oral glucose tolerance tests and MRI scans at the beginning and end of each study phase to measure glucose and insulin levels and assess body composition. During the sleep restriction phase, participants delayed bedtime by 1.5 hours per night, resulting in an average sleep duration of 6.2 hours per night—reflecting the average sleep duration of U.S. adults with insufficient sleep. 

The study found that restricting sleep to 6.2 hours or less per night over six weeks increased insulin resistance by 14.8% in both pre- and postmenopausal women. Postmenopausal women exhibited more severe effects, with insulin resistance increasing by as much as 20.1%. Premenopausal women showed a rise in fasting insulin levels, while both fasting insulin and fasting glucose levels tended to increase in postmenopausal women. 

Marie-Pierre St-Onge, Ph.D., senior author on the study, highlighted the need for more insulin to normalize glucose levels in conditions of sleep restriction. She expressed concern that prolonged insufficient sleep among individuals with prediabetes could accelerate the progression to type 2 diabetes. 

The study also explored whether changes in body weight contributed to alterations in insulin and glucose levels, given that people tend to eat more when sleep is restricted. However, the effects on insulin resistance were largely independent of changes in body weight. Importantly, when participants returned to their typical 7-9 hours of sleep per night, insulin and glucose levels normalized. 

Corinne Silva, Ph.D., Program Director at the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), highlights the study’s contribution to understanding the health effects of small sleep deficits in women across different life stages and backgrounds. Researchers are planning additional studies to further explore how sleep deficiency affects metabolism in both men and women and to investigate sleep interventions as a tool in type 2 diabetes prevention efforts. 

In summary, the study underscores the critical role of adequate sleep in minimizing the risk of type 2 diabetes, emphasizing the importance of addressing sleep disturbances, especially among women, as part of broader preventive health measures. 

News Reference  

National Institute of Health, Chronic sleep deficiency increases insulin resistance in women, especially postmenopausal women, Chronic sleep deficiency increases insulin resistance in women, especially postmenopausal women | National Institutes of Health (NIH).