Women who routinely don’t get enough sleep, especially those who have gone through menopause, may be at a higher risk for developing type 2 diabetes, according to a new study published on November 13 in the journal Diabetes Care.
The findings suggest that inadequate sleep impacts insulin production and metabolism, said coauthor Marie-Pierre St-Onge, PhD, an associate professor of nutritional medicine at the Columbia University Institute of Human Nutrition in New York City, in a press release.
“The bottom line is that getting adequate sleep each night may lead to better blood sugar control and reduced risk for type 2 diabetes, especially among postmenopausal women,” said Dr. St-Onge.
Women More Likely to Report Not Getting Enough Sleep
Previous studies on inadequate sleep and diabetes risk have focused mainly on men, and usually looked at very short but intense bouts of sleep deprivation. It’s important to study how chronic sleep disturbances specifically impact women’s health for a few reasons, according to the authors. “Throughout their lifespan, women face many changes in their sleep habits due to childbearing, child-rearing, and menopause — and more women than men have the perception they aren’t getting enough sleep,” said St-Onge.
Most U.S. Adults Don’t Get Enough Sleep
A study from Brigham and Women’s Hospital published in March 2023 found that most adults are sleeping about six hours and 27 minutes each night, and nearly 30 percent slept less than six hours. It’s recommended that adults get at least seven hours of sleep each night.
Not getting enough sleep on a regular basis is linked to many chronic health problems, including heart disease, kidney disease, high blood pressure, stroke, obesity, and depression, according to the National Heart, Lung, and Blood Institute.
Less Sleep Impacted the Way Women Processed Sugar
The new study enrolled 38 women between ages 20 and 75 years old who had healthy sleep patterns (at least seven to nine hours per night) and normal fasting blood sugar levels. However, all participants also had heart disease or elevated risks for heart disease because of having overweight or obesity, a family history of type 2 diabetes, high cholesterol or triglycerides, or some combination of these factors.
To establish a baseline for typical sleep patterns, the women wore a sensor on their wrists and kept nightly sleep logs for two weeks. Participants then completed two six-week study phases in a random order: one where they continued to follow their healthy sleep patterns, and one where sleep was restricted. In between, they took a six-week break to recalibrate.
During the adequate sleep phase of the trial, participants maintained their typical bed and wake times and slept an average of 7.5 hours per night.
In the sleep restriction phase, the women were told to delay their normal bedtime by 1.5 hours per night, but to continue waking up at the same time. On average, the women in this phase slept an average of 6.2 hours per night — about the amount that the average American gets, the authors point out.
At the beginning and end of each study phase, participants completed an oral glucose tolerance test to measure blood sugar and insulin levels, along with an MRI to scan for body fat levels.
What’s the Relationship Between Blood Sugar, Insulin, and Diabetes?
Insulin helps regulate sugar (or glucose) in the body. When a person develops resistance to insulin, it means their body becomes less effective at processing glucose, which in turn increases the risk for prediabetes or type 2 diabetes, according to the authors.
Healthcare providers sometimes use an oral glucose tolerance test (OCTT) to screen for type 2 diabetes by measuring the body’s response to glucose, according to Mayo Clinic. The test identifies abnormalities in the way the body handles glucose after a meal.
In the group where sleep was limited, insulin resistance increased by 14.8 percent on average. For postmenopausal women, insulin resistance increased by as much as 20.1 percent. In other words, the women lacking sleep needed more insulin to normalize blood sugar.
In premenopausal women, sleep restriction caused fasting insulin levels to go up, while levels of both fasting insulin and fasting glucose tended to increase in postmenopausal women.
“Over a longer period of time, ongoing stress on insulin-producing cells could cause them to fail, eventually leading to type 2 diabetes. 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,” said St-Onge in the release.
The researchers also looked at whether any weight gained by the women during the study could have caused the increase, as people tend to eat more in sleep-restricted states. However, they found that effects on insulin resistance were largely independent of changes in body weight, and once the women started sleeping their typical seven to nine hours per night again, their insulin and glucose levels returned to normal.
Insulin Resistance Associated With Higher Risk for Hypertension, Heart Disease and Some Types of Cancer
If you accept the authors’ conclusions at face value, then it does appear that menopause-related sleep issues could potentially increase the risk for diabetes, says Sun Kim, MD, an associate professor and endocrinologist at Stanford Medicine in California.
However, insulin resistance is not synonymous with prediabetes or diabetes, says Dr. Kim. You have to have insulin resistance before you are diagnosed with prediabetes, and chronic insulin resistance can lead to prediabetes or type 2 diabetes, per the Cleveland Clinic.
“Individuals with insulin resistance tend to be at higher risk for prediabetes/diabetes and other diseases including hypertension, dyslipidemia [high cholesterol], cardiovascular disease, and some forms of cancer,” she says.
But in this study, insulin wasn’t directly measured during the OGTT — a surrogate marker was used, and the findings shown here don’t necessarily show that less sleep increased insulin resistance, says Kim.
Why Could Lack of Sleep Cause the Body to Respond Less Effectively to Glucose?
Researchers still don’t completely understand why sleeping less on the regular may cause this change. “It’s possible that shortening sleep alters rhythmic processes in the body,” says St-Onge.
Kim is not certain this study proved that short duration worsened insulin resistance, but she offers a potential theory if that is indeed the case. “Short sleep duration may worsen insulin resistance through multiple pathways, including increasing ‘stress,’ or cortisol, inflammation, and sympathetic nervous system [response],” also known as flight-or-fight reactions, she says. There could also be changes in fat distribution or fat function, although this study did not find major differences in body fat levels, she adds.
If Sleep Is a Struggle, Try This
Sleep issues often plague women during menopause. Depending on your medical history and lifestyle, hormone therapy may help, according to the North American Menopause Society.
Lifestyle changes can also help manage sleep issues. The University of Maryland Medical System offers the following tips:
- Avoid caffeine and spicy foods.
- Follow a regular bedtime routine that includes a calming activity before getting into bed.
- Don’t eat a large meal right before bed.
- Exercise daily but not too close to bedtime.
- Go to bed and get up at the same time every day.
- If you smoke, try to quit.
- Limit alcohol.
- Keep your home cool and quiet at night.
- Practice meditation, deep breathing, or other mindfulness techniques.
- Limit screen time before bed. Better yet, keep phones and tablets out of your bedroom altogether, if possible.