Anyone taking steps to better manage their diabetes knows the importance of blood glucose monitoring, a balanced diet and physical activity. In contrast, the importance of sleep can be underestimated as we navigate through our increasingly busy and stressful lives. This is a mistake. Sleep, especially good quality sleep, is critical for diabetes self-management.
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What is meant by good quality sleep?
Good quality sleep usually involves:
• Falling asleep within 30 minutes.
• Waking up no more than once.
• Spending no more than 20 minutes awake after initially falling asleep.
• Spending 85% or more of total time in bed asleep.
• Feeling satisfied with sleep.
Poor quality or excess sleep is referred to as “sub-optimal sleep.” Sleep quality is also determined by the stages of sleep, which are:
• Non-rapid-eye movement (NREM), which comprises stages 1, 2 and 3. Stages 1 and 2 are light sleep. Stage 3, which is deep sleep, involves the production of slow delta waves, when restorative processes such as tissue repair occurs.
• Rapid-eye movement (REM) sleep is an active stage of sleep — you can tell when someone is in this stage because their eyes move rapidly. Dreaming occurs during this phase of sleep, which is important for learning, memory and mood.
There are approximately four to six sleep cycles during a single night’s sleep, each cycle lasting for an average of 90 minutes. The duration of deep sleep is longer in the first half of the night, reducing toward the end. In contrast, REM sleep progressively increases in duration over the night.
This pattern and timing of deep and REM sleep help regulate the natural secretion of melatonin (the sleep-promoting hormone), which is secreted early in the night, with its levels reducing toward morning. In contrast, cortisol (a stress hormone) is secreted in the second half of the night’s sleep, when REM sleep increases in frequency and duration. Therefore, good quality sleep is important for the normal progression of the sleep cycle and other critical body processes that occur during sleep.
General indicators of poor sleep quality:
• Sleep duration per night less than six hours or more than 10 hours for adults ages 26 to 64 years.
• Taking more than 45 minutes to fall asleep.
• Awakening more than three times overnight (each awakening more than 5 minutes).
• Being awake for more than 40 minutes after initially falling asleep.
• Spending less than 75% of time in bed asleep.
• Taking more than three naps and 100 minutes of naps per day.
What is the connection between sleep quality and diabetes?
Dr. Mark Heyman, PhD, diabetes psychologist and certified diabetes care and education specialist at the Center for Diabetes and Mental Health in California, says, “It is very common for people with diabetes to report poor sleep quality. In my experience, it is not something we talk about enough or assess for in people with diabetes.”
Interestingly, diabetes and sleep have been shown to influence each other. Diabetes is associated with:
• Insufficient sleep.
• Frequent sleepiness during the day.
• Frequent need to use sleeping pills.
• Urge to urinate during the night.
• Sleep disorders, including insomnia, sleep apnea (which involves brief obstruction of breathing during sleep) and restless leg syndrome (where uncomfortable sensations lead to an irresistible urge to move the legs). In turn, poor-quality sleep can lead to abnormal glucose metabolism and insulin resistance, which can increase the risk of diabetes development and negatively impact blood sugar management in diabetes.
In people with low glucose tolerance (also known as prediabetes, in which blood glucose levels are higher than normal but not high enough to result in a diabetes diagnosis), lower duration of deep sleep has been shown to increase the number of nighttime awakenings, delay the onset of REM sleep, and increase the secretion of melatonin at the time of awakening instead of during the night. Incidentally, in addition to promoting sleep, melatonin is considered to modulate insulin release and glucose metabolism. Therefore, the delayed secretion of melatonin could reduce insulin release and further decrease glucose tolerance in the morning. Since the control of blood glucose levels is already impaired in individuals with diabetes, such a reduction in deep sleep duration could negatively impact self-management efforts.
The emotional toll of poor sleep in diabetes
Poor sleep, as well as low blood glucose during the night, has been linked to depression, fatigue, cognitive impairment and anxiety among people with diabetes. This can impact daytime functioning, which can affect your ability to engage in self-care behaviors such as monitoring of blood glucose, taking medicines in a timely manner, and meal planning. Poor sleep can also trigger emotional eating behavior, negatively affecting blood glucose control.
Sleeping for less than five hours could trigger an increase in the levels of ghrelin (an appetite-stimulating hormone) and a decrease in leptin levels (an appetite-suppressing hormone). Therefore, the impact of poor sleep on eating isn’t just emotional; it has a physical aspect, too, and can increase feelings of hunger and, therefore, over-consumption of energy-dense foods and sweet foods that increase blood glucose levels.
Can oversleeping be a problem too?
Oversleeping, which leads to excessive REM sleep in the morning, could also affect blood sugar levels. In the latter part of the night, the release of cortisol prepares the body for waking up and increases blood glucose levels. When you wake up in the morning after sufficient sleep, your body uses this glucose. However, when you sleep for a longer duration than normal, the excess blood sugar is not utilized, leading to abnormally high blood sugar levels, which can be especially harmful to people with diabetes.
What causes poor sleep quality in people living with diabetes?
“There are several challenges to getting good quality sleep specific to people with diabetes,” says Heyman, “First is overnight blood sugar control. People who have high and low blood sugars at night tend to have lower quality of sleep.” According to Heyman, potential information overload is another challenge to achieving good quality sleep, especially with continuous glucose monitoring (CGM) and the frequency of alarms associated with it. He explains, “With blood sugars always available on the phone, there can be a temptation to constantly be monitoring blood sugar, even at night. Excessively thinking about one’s blood sugar keeps the mind active and can cause anxiety, making sleep more challenging.” Depression and neuropathic pain are other possible causes of poor sleep among people with diabetes.
How can you improve sleep while managing diabetes?
“I would encourage people to work with their healthcare team to find strategies to keep overnight blood sugars in range,” says Heyman, “I would also encourage people on CGM to adjust their overnight alarm settings to go off less frequently while still keeping them safe. Finally, I would encourage people to use stress-management techniques such as mindfulness, progressive muscle relaxation, and limiting screen time before bed to help them manage anxiety and improve their sleep.” Sleep quality, as well as anxiety regarding glucose levels at night, could be improved using closed-loop glucose control systems, as opposed to open-loop systems. Closed-loop systems automatically calculate and administer basal (background) insulin, largely eliminating the need for alarms, which could improve sleep quality for both people with diabetes and their caregivers or family. (In contrast, open-loop systems alert the user to abnormal glucose levels through alarms and require the user to calculate the dose of insulin for high glucose levels.)
Sleep disorders such as insomnia and obstructive sleep apnea can be effectively managed by cognitive-behavioral therapy (CBT) and continuous positive airway pressure (CPAP), respectively. With guidance from your healthcare provider, you could also consider pharmaceutical intervention such as melatonin supplements. Sufficient physical activity and other lifestyle changes, such as consuming a healthy diet, can also improve sleep, without adverse effects on glucose levels.
How can diet improve sleep?
Currently, there is not much clarity regarding how specific foods or diets can improve sleep in people with diabetes. However, research suggests that sleep quality could be improved by following a diet richer in proteins than carbohydrates or by following a Mediterranean diet (an eating style that tends to be rich in vegetables, fruits, grains, beans, nuts, olive oil and fish). Both of these diets have been shown to improve the control of blood glucose levels among individuals with type 2 diabetes.
In some cases, tryptophan supplementation has been shown to aid sleep. Tryptophan is an amino acid that increases serotonin levels — a precursor to the sleep hormone, melatonin. Foods high in tryptophan include chicken, eggs, cheese, fish, peanuts, sesame seeds and turkey. For individuals with vitamin B deficiency, supplementation of this vitamin could improve sleep quality. Alternatively, eating vitamin-B-rich foods such as whole grains, meat, eggs, legumes, seeds and dark, leafy vegetables may be beneficial.
Additionally, deep sleep can be improved by consuming sufficient food to meet your calorie requirements, without exceeding these requirements.
Sleep for self-care
Considering this association between sleep and diabetes, the American Diabetes Association has recommended that sleep pattern and duration be assessed as part of diabetes management. So, when creating your self-management plan, make sure you address your sleep patterns. You and your diabetes could benefit from some well-deserved shut-eye — not too much, though!
Want to learn more about sleeping well with diabetes? Read “Getting the Sleep You Need,” “Eating for Better Sleep” and “Sleep and Diabetes: What’s the Connection.”
