Type 2 Diabetes and Sleep: What’s the Connection?

If you have type 2 diabetes, you probably pay attention to what you eat and try to stay physically active. But there is another important component of managing your condition that you may not always prioritize: sleep.

You may have heard that making sure you get good sleep is an important part of staying healthy, particularly if you have type 2 diabetes. But what exactly is the connection between sleep and diabetes, and why should it be considered a crucial pillar in managing your condition? Here’s what you need to know.

Sleep and Insulin Resistance

“Sleep is a time for your body to rest and repair, but a lot of things happen as you move through the sleep stages throughout the night,” says Josie Bidwell, DNP, an associate professor at The University of Mississippi School of Medicine in Jackson. During sleep, says Bidwell, your brain stores memories, your muscles are repaired, your heart rate goes down, and your blood pressure falls. Lower resting heart rate and blood pressure are particularly important if you have type 2 diabetes, since having the condition makes you twice as likely to be diagnosed with heart disease, per the Centers for Disease Control and Prevention (CDC).

Sleep is also essential for hormone regulation, and insulin is a hormone. “In general, poor sleep plays a role in insulin resistance,” says Bidwell, which occurs when your body has difficulty using insulin to move glucose from your blood into cells. This can result in high blood sugar. “If you are struggling to gain control of your blood glucose, looking at your sleep and doing what you can to get the recommended 7-plus hours can be a game changer,” Bidwell says.

Seven hours is actually a sweet spot for sleep. In a study on adults who had prediabetes or were recently diagnosed with — but untreated for — type 2 diabetes, sleeping fewer than five hours or longer than eight hours per night was associated with a higher A1C level compared with those who got a more moderate amount of sleep, according to a study published in May 2019 in the journal Diabetes Care. Sleeping fewer than six hours per night was also associated with a higher BMI, which increases the risk for type 2 diabetes and makes blood sugar levels harder to control. (Losing just a few pounds can improve blood sugar control and reduce the need for medication, according to the American Diabetes Association [ADA].)

While it’s not clearly understood why sleeping longer may be detrimental to your health, there are many potential hormonal changes that occur with sleep loss. “There is a biochemical cascade driven by inflammatory substances, such as cytokines, after sleep loss that can set someone up for insulin resistance,” notes Bidwell. What’s more, as the Diabetes Care study points out, sleep deprivation activates your sympathetic nervous system, responsible for your fight-or-flight stress response, which can also decrease insulin sensitivity. This is an area of ongoing research.

How Uncontrolled Blood Sugar Can Disrupt Sleep

Along with physiological changes, sleep deprivation also prompts people to consume more calories and decreases their ability to make nutritious choices and maintain a healthy lifestyle. This can lead to increased risk for diabetes and obesity, which itself is a risk factor for diabetes, suggests a paper published in November 2016 in the journal Current Diabetes Reports.

And the relationship between sleep and blood sugar levels goes the other way, too. “When blood sugar runs higher [than normal], you urinate more often,” says Bidwell. In other words, extra blood sugar goes into the urine and pulls water from your tissues, so you pee more, notes Mayo Clinic. You may find that you’re waking up multiple times per night to go to the bathroom, which can disrupt sleep. It’s also important to point out that if your blood sugar dips too low (below 70 mg/dL) in your sleep — a condition called nocturnal hypoglycemia — you may also experience restless sleep, have nightmares, and sweat in your sleep, according to Johns Hopkins Medicine.

In addition, patients with diabetes are up to three times more likely to have depression compared with the general public, but just one-quarter to one-half get help, according to the CDC. That’s significant, because sleep problems and depression go hand in hand, suggests research published in February 2019 in the Journal of Cellular and Molecular Medicine. Bottom line: Having depression puts you at increased risk for insomnia, and, conversely, insomnia may elevate your risk of depression.

Taken altogether, it’s hardly a surprise that in a study of more than 7,000 middle-aged and older adults with diabetes, one-quarter reported having a sleep disorder. About 77 percent said that they had sleep problems, such as difficulty falling asleep, sleep apnea, or daytime sleepiness, concluded research published in October–December 2016 in the journal Diabetes & Metabolic Syndrome: Clinical Research & Reviews.

How Sleep Impacts a Healthy Diet and Weight Loss

There are two main hunger hormones: leptin, which turns off your appetite, and ghrelin, which stimulates hunger. “When you don’t sleep well, leptin goes down and ghrelin goes up,” says Bidwell. The result is that you’re less satisfied with the food you’re eating but also hungrier, particularly for sugary foods and other simple carbohydrates that can be easy sources of quick energy for the body and brain. “People say, ‘I have all these cravings and I have no willpower,’” she notes. “It’s rarely ever just about willpower; there are other factors, like lack of sleep, setting people up for not being as successful as they could be.”

It’s not just what you eat but how much. In a meta-analysis of 11 studies, people who were sleep deprived consumed 385 extra calories per day compared with a control group, according to research published in November 2016 in the European Journal of Clinical Nutrition. Not only are you up against that hunger hormone driving you to eat more, but there are simply more hours when you are awake and eating. “Eating extra calories will yield a higher blood sugar, which can worsen insulin resistance,” says Chauntae Reynolds, PharmD, CDCES, a spokesperson for the Association of Diabetes Care & Education Specialists who’s based in Indianapolis.

How to Improve Your Sleep if You Have Diabetes

The healthy sleep guidelines that apply to everyone are especially important to follow if you have diabetes, says Reynolds. Disturbed sleep and waking up often in the middle of the night are associated with worsening levels of diabetes self-care, found a study published in September 2018 in the journal Acta Diabetologica. (Self-care in diabetes includes the routines that you regularly perform to manage the condition.) And a study published in July 2020 in the journal Diabetologia found that sleeping fewer or more than 7 hours a day was associated with a greater risk of earlier death.

Here’s what Reynolds advises patients to do to get better sleep with type 2 diabetes.

• Set a bed- and wake time. “On the weekend, you might sleep in, and then the Monday blues set in, and it’s tough to get up. So keep a set wake and bedtime for every day, which is important for sleep quality,” she says.
• Go screen free. The time to scroll through your phone is not when you climb into bed, as blue light suppresses melatonin, a hormone necessary for falling asleep.
• Exercise. Physical activity not only helps improve insulin sensitivity by encouraging muscle cells to take up blood glucose for energy but is also associated with better sleep, notes Johns Hopkins Medicine.
• Clean up your sleep hygiene. Keep your room dark, cool, and quiet to set the stage for a restful night (and waking up less).
• Find your wind-down routine. Take a warm shower, do a relaxing skincare routine, read a book, or write in a journal — whatever helps you prepare for bed. Keeping a mood journal (writing about your feelings and emotions) can play a role in decreasing anxiety surrounding chronic conditions like diabetes, suggests the ADA.
• Drink smart. Avoid caffeine at least 8 hours before bedtime, and don’t drink alcohol before bed. Both can cut into sleep quality, says Reynolds.
• Avoid having a heavy meal. Not only can heavy meals impact your blood sugar levels, but eating one close to bedtime can keep your blood sugar high overnight, which will affect the quality of your sleep, says Reynolds.