The interaction between sleep and blood glucose: What happens?

Marie-Luise Huber
7 min.
The interaction between sleep and blood glucose: What happens?
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Blood sugar (or glucose) can have a significant impact on your sleep patterns. Did you know that it could even be the reason for your sleep problems?

The relationship between sleep and blood sugar is bidirectional. In one direction, your sleep directly affects your blood sugar level (the next day). In the other direction, blood glucose levels before and during the night's rest affect sleep.

Sleep and glucose: why it matters

Blood sugar affects sleep, and sleep affects physical health. Short sleep duration - less than seven hours in a 24-hour period - can have a significant impact on health. This explains why adults with too little sleep are at higher risk for chronic diseases such as diabetes, obesity and heart disease.

So getting your sleep habits under control will have a positive impact on your health and life expectancy. We'll show you how to do that by monitoring your blood glucose levels.

Sleep is important for your body's recovery process. If you don't sleep enough, various changes occur in your body.

Sleep influences insulin levels

Sleep affects hormone levels and circadian rhythms. The circadian rhythm naturally controls your sleep-wake cycle by responding to things like light and darkness.

A small group of nerve cells make up what is called the "master clock" in your brain. This internal clock controls hormone release, temperature, eating habits and digestion. For it to function optimally, a regular day-night rhythm is required.

When your circadian rhythm gets out of whack, your body's metabolism can worsen - and you increase your risk for diabetes.

In addition, lack of sleep reduces insulin sensitivity, so the body has to produce more insulin to stabilize blood glucose levels. This eventually leads to glucose intolerance and diabetes.

Unfortunately, even a single night of insufficient sleep can impair your body's ability to use insulin effectively. For example, your body reacts more strongly to certain foods or you have more cravings during the day after a restless night.

Sleep regulates hunger hormones

Leptin and ghrelin are two hormones that regulate your appetite. Leptin has several functions in your body. Two of the main ones are long-term energy regulation and metabolism.
Let's look at the mechanism behind it and why it's related to sleep.

The fat cells in your body release leptin to tell your brain that you have enough energy. When it is released, it suppresses your appetite and you feel satisfied. When leptin levels are low, you feel hungry.

Several studies have found that short sleep duration lowers leptin levels, which leads to overeating and weight gain. The desire to eat more, in turn, leads to increased intake of carbohydrates, which spike blood sugar levels.

Ghrelin has the opposite function of leptin: high ghrelin levels increase appetite and may be the result of sleep deprivation.

The increase in ghrelin levels triggers a feeling of hunger, which leads to eating more carbohydrates, which in turn increases blood glucose levels.

In short, less sleep leads to more cravings and overeating and may be the reason for weight gain.

Sleep influences the activity of the sympathetic nervous system

Lack of sleep or even insufficient sleep can increase the activity of the sympathetic nervous system, which controls the "fight-or-flight" response. Lack of sleep can cause this "fight-or-flight" mode to kick in during the day and at night, releasing stress hormones such as cortisol. And cortisol can lead to chronically elevated blood sugar levels. Long-term consequences of these high blood sugar levels include prediabetes, diabetes, or metabolic syndrome.

Sleep regulates inflammation

Research shows that sleep deprivation increases inflammation levels in the body. Similar to the effects on insulin levels, this effect can occur after just one sleepless night. Inflammation is one of the body's defense mechanisms, providing valuable protection against viruses and bacteria.

Sleep affects brain function

Glucose is the brain's fuel. It provides the energy it needs to perform its functions. When sleep is deprived, brain activity decreases significantly. You may have noticed that you can concentrate better after eating something sweet. At least for a while.

Sleep helps regulate body fat

As mentioned above, sleep contributes to the maintenance of body weight in many ways, including the regulation of hunger hormones and insulin levels. In addition to the hormonal effects, lack of sleep also increases the level of free fatty acids in the blood. These high fatty acid levels reduce insulin sensitivity and hinder the body's ability to metabolize fat.

We assume that these are enough reasons to emphasize the importance of sleep.
So let's take a look at your blood sugar levels when you sleep.

Blood glucose level during sleep

In a healthy person, blood sugar levels rise and fall during sleep, which is normal. Some of the changes can be attributed to your sleep phases (usually lower during REM), others to the glass of alcohol (large fluctuations) you drank with dinner, or they can also be related to your circadian rhythm (where your liver is most active between 2 and 4 am).

In general, we have found that blood glucose levels tend to be lower during sleep than when you are awake.
Currently, there are no general recommendations for nighttime blood glucose levels, but it seems safe to say that the healthy range during the night is between 70 and 100 mg/dl.
So you may well be lower than the optimal range of 80-110 mg/dl. However, if you find that you wake up several times during the night and your blood glucose levels are in the lower range, we recommend that you optimize your eating and sleeping habits.

Another fascinating fact about sleep and blood sugar is the phenomenon of dawn.

The dawn phenomenon is a process that occurs in everyone. In the early morning hours, certain hormones (growth hormone, cortisol and catecholamines) cause the liver to release sugar into the bloodstream. This process can cause a short-term spike in blood sugar levels. This is the body's "natural alarm clock".

For most people, the dawn phenomenon usually occurs between 4 and 8 a.m., depending on their sleep-wake cycle. Your blood sugar level should drop again within a few hours.

High blood glucose levels (>110 mg/dl)

High blood sugar levels before bedtime can affect the nervous system, making it difficult to fall asleep and stay asleep through the night. This can trigger insomnia and increase cortisol and adrenaline levels so that the body cannot fully relax.

You may have to go to the bathroom more often, which disrupts your sleep. This is because your kidneys are trying to flush the excess glucose out of your body.

High blood sugar can make you feel dehydrated and wake up from sleep to rehydrate with a glass of water.

They can also make you feel hot or irritable and restless, making it harder to fall asleep.

Niedriger Blutzucker (< 70 mg/dl)

Hypoglycemia can occur in both diabetics and non-diabetics. It can also severely affect your sleep. Your blood sugar level can drop due to stress, alcohol, insulin resistance, etc.

Sleep disturbances caused by high/low blood glucose levels can lead to a problematic cycle of poor sleep and poor blood glucose control.

What does your sleep look like?

Your blood sugar level can have a significant impact on how your body feels and functions. Therefore, a stable blood sugar level can be an important factor in your overall well-being.

With Hello Inside, you can track your blood glucose levels over time using a continuous glucose monitor to help you make decisions that benefit your health.

Are you ready to take the first step? Take our quiz now to find out which Hello Inside program is right for you.

 

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Marie-Luise Huber
Luise has spent the last 15 years studying nutrition and guiding people toward healthy lifestyles. Before becoming Head of Nutrition at Hello Inside, she helped parents plan the right lunches for their children. Luise also optimized food ingredients in Central and Eastern European countries. She has helped more than 1000 people of all ages on their weight loss journey. Her favorite tip for balancing blood sugar is exercise, as Luise loves to run, ski or bike. And she loves to bake (not always blood sugar friendly).
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