A good night’s sleep is generally measured as between seven and nine hours. If you manage that, you tend to be more alert, well-rested, and at a lower risk of certain chronic health conditions. On the other hand, getting less than seven hours has the opposite effect, and a new study finds that this may be true even if you only have a brief period of insufficient sleep.
Research recently published in the journal Diabetes Care took a look at what happened when women who typically got enough sleep cut back on their usual sleep total by just 90 minutes. The goal was to see whether prolonged mild sleep restriction would impact glucose metabolism in women. According to the findings, fasting insulin levels went up with sleep restriction, especially in postmenopausal women. The researchers say the findings provide a possible modifiable risk factor behind insulin resistance, which could help with diabetes prevention.
Dr. Corinne Silva, Program Director in the Division of Diabetes, Endocrinology, & Metabolic Diseases at the National Institute of Diabetes and Digestive and Kidney Diseases, says, “This study provides new insight into the health effects of even small sleep deficits in women across all stages of adulthood and racial and ethnic backgrounds. Researchers are planning additional studies to further understand how sleep deficiency affects metabolism in men and women, as well as explore sleep interventions as a tool in type 2 diabetes prevention efforts.”
To investigate the impact of sleep deficiency on glucose metabolism in women, the researchers recruited 40 women between the ages of 20 and 75 who habitually slept between seven and nine hours per night, had normal fasting glucose levels, and who had higher risk of cardiometabolic disease due to being overweight or obese or having a family history of type 2 diabetes, increased lipid in the blood, or cardiovascular disease.
The women spent six weeks of the study getting their usual sleep totals and six weeks going to bed 90 minutes later but waking up at the same time. There were six weeks between each of these periods, as well. Their nightly sleep was tracked by a wrist sensor. Prior to the study, they also had their baseline sleep measured with the sensor for two weeks.
The participants’ average sleep total during the healthy sleep phase was 7.5 hours per night, compared with 6.2 hours in the insufficient sleep phase. The researchers found that when their sleep was restricted, the women had an average increase in insulin resistance of 14.8%, while it was up to 20.1% in postmenopausal women. In women of that age, fasting insulin and fasting glucose levels both tended to rise at this time, while for premenopausal women, there was just an increase in fasting insulin levels.
With 6.2 hours being the median sleep duration of American adults who don’t get enough sleep, the findings could have broad implications.
Dr. Marie-Pierre St-Onge, senior author and director of the Center of Excellence for Sleep and Circadian Research at Columbia University, says, “What we’re seeing is that more insulin is needed to normalize glucose levels in the women under conditions of sleep restriction, and even then, the insulin may not have been doing enough to counteract rising blood glucose levels of postmenopausal women. If that’s sustained over time, it is possible that prolonged insufficient sleep among individuals with prediabetes could accelerate the progression to type 2 diabetes.”
The findings mirror those of past studies on the dangers of insufficient sleep. That includes a study that found getting only five hours of sleep per night puts people at risk of living with multiple chronic diseases. You can read more about that here.