STUDENT CONTRIBUTOR: Michael Sheng | School of Nutrition, Ryerson University
December 7, 2020
A good night's sleep provides us with some really great health benefits; increased concentration and productivity, more energy, better immune function, and muscle growth for athletes. But... can sleep help with managing blood sugars, too?
The Effect of Sleep on Diabetes
While there are many benefits to a good night’s rest, it’s especially important for people with diabetes, or at risk of developing diabetes to sleep well. Poor sleep is linked with insulin resistance, with one study reporting 23% higher blood glucose levels in poor sleepers and 48% higher levels of blood insulin. Staying up late and sleeping less is also associated with increased risk of developing type 2 diabetes.
A lack of sleep can induce a hormonal imbalance that often causes us to eat more than we normally would; perpetuating the cycle of high blood sugars and poor sleeping habits. When we stay up late, the body tends to produce less insulin and more cortisol - a hormone which helps keep you alert and awake. Increased amounts of cortisol in our bodies may make it harder for the brain to shut down as you start to wrap up your day and could cause you to feel a little more stressed or anxious. Studies show that this effect is especially important in youth at and increased risk for type 2 diabetes, since they need extra sleep for proper growth and development.
Sleep loss is also shown to lead to increased risk for developing diabetes due to changes in the body’s metabolism, appetite, and energy expenditure, as shown below.
The Effect of Diabetes on Sleep
On the flip side, symptoms of diabetes can also influence our sleep habits. Having diabetes can lead to more disturbances through the night while we're trying to sleep:
high blood sugars tend to dehydrate you and make you thirsty, so you have to get up to get a drink,
when you are drinking more, you need to go to the bathroom more, interrupting your sleep for those extra trips to the bathroom,
living in a larger body associated with diabetes can lead to sleep apnea, which interrupts your breathing during sleep, and/or
high blood sugars can also lead to Restless Leg Syndrome (RLS) and insomnia, which can make it difficult to fall asleep.
Nocturnal hypoglycemia, a.k.a. 'hypos' or overnight low blood sugar is identified as a drop in blood sugar levels overnight. Common signs of overnight low blood sugars are waking up with a headache, nausea, dry mouth, light-headedness, or sweating. If you experience these symptoms, you should start recording your fasting blood sugar levels in the morning. If they are below 3.8mmol/L (70 mg/dL), it’s recommended you contact your doctor. If you're experiencing low blood sugars overnight, think back to what you did during the day. Were you unusually active? Did you eat dinner later than usual? Or, maybe you had a few drinks (alcohol) with a friend? Workouts, team sports, or intensive exercise can also lead to overnight hypoglycemia up to 48 hours after the activity. It’s recommended to avoid exercise within two hours of bedtime to decrease your chances of going low while you're sleeping.
Sometimes, overnight lows go unnoticed due to a lack of symptoms. You may not feel or wake up to your lows. This is known as ‘hypoglycemia unawareness’. Be sure to regularly track your blood sugar levels before and after sleeping. If your blood sugar levels are below 3.8mmol/L (70 mg/dL) in the morning, speak to your doctor or diabetes educator. Any time your your blood sugar levels are below 5.5mmol/L (100 mg/dL) before bed, it's always a good idea to consider having a small snack of carbohydrate paired with protein (e.g., whole wheat crackers with cheese, or plain Greek yogurt with berries).
How to Improve Sleep for Diabetes Management
One of the best ways to use sleep to your advantage in managing blood sugars - for both people type 1 and type 2 diabetes - is to have a consistent sleeping schedule. Studies show that going to bed and waking up at the same time every night helps with diabetes management. Your body will get used to the constant sleep schedule and as a result, you are more likely to get better sleep. This also means having the same sleep schedule on weekdays and weekends.
Exercise can also help improve your sleep by reducing blood sugars naturally, helping support weight management goals and reducing the risk of sleep apnea. However, as previously mentioned, it's recommended that you avoid exercise within two hours of bedtime, due to the risk of overnight lows.
Aside from diabetes management, exercise also has the added benefits of improving your mental and cardiovascular health, and protecting against Alzheimer’s disease and dementia. The Canadian Physical Activity Guidelines recommend 150 minutes of moderate aerobic activity each week, or about 20 minutes per day. Getting and staying active can include a brisk walk, a light jog, water aerobics, biking, or working around the house or in the garden. Try to be sure to get back to basics with daily tasks like mowing the lawn, taking the stairs or parking farther way from the door to get your steps in.
Avoiding screen time (e.g., computer, phone, TV, video games) before bed can also help you sleep better. Feel free to pick up a book to read as you drift off! Alcohol should also be limited before bed, as it can suppress the anti-diuretic hormone, making you more likely to have an interrupted sleep because you have to get up and go to the washroom in the middle of the night.