Men who sleep too much or too little may be at greater risk for diabetes.
Senior author Femke Rutters, Ph.D., of the VU Medical Centre in Amsterdam, the Netherlands, and colleagues report their findings in the Journal of Clinical Endocrinology & Metabolism.
Insulin is a hormone produced by the beta cells of the pancreas that transports glucose from the bloodstream into the body's cells, where it is used for energy. If beta cells cannot produce enough insulin or the body does not correctly respond to the hormone, this results in high blood glucose levels.
Obesity and lack of exercise are two lifestyle factors known to raise the risk of diabetes. For this latest study, Rutters and colleagues set out to determine whether sleep duration could also play a role in diabetes development.
Poorer glucose metabolism for men with limited or excess sleep
The team analyzed data of 788 healthy men and women aged 30-60 years from across 19 European countries. All subjects were part of the European Relationship between Insulin Sensitivity and Cardiovascular Disease (EGIR-RISC) study.
The researchers assessed how many hours sleep participants got each night, and their physical activity levels were assessed using a single-axis accelerometer - a movement sensor.
Subjects' risk of diabetes was assessed using a hyperinsulinemic-euglycemic clamp, which measures how well the body uses insulin.
"In men, sleeping too much or too little was related to less responsiveness of the cells in the body to insulin, reducing glucose uptake and thus increasing the risk of developing diabetes in the future," explains Rutters.
In addition, men who slept fewer or more than 7 hours a night had higher blood sugar levels than those who slept an average of 7 hours.
Women's diabetes risk may not be affected by sleep
No such associations were identified among women, the researchers report.
In fact, the team found that the cells of women who slept fewer or more than 7 hours a night were more likely to respond to insulin, and their beta cells had better function, suggesting that lack of sleep does not raise women's diabetes risk.
Still, the researchers say their findings highlight the importance of getting a good night's sleep - particularly for men.
"Even when you are healthy, sleeping too much or too little can have detrimental effects on your health. This research shows how important sleep is to a key aspect of health - glucose metabolism."
Femke Rutters, Ph.D.