Understanding Nocturnal Hypoglycemia

Published on May 19, 2021

Medically reviewed by Danielle Weiss, MD

When a person is sleeping at night and their blood glucose falls below 70 mg/dL, this is called nocturnal hypoglycemia. This is a common occurrence that can be very dangerous.

Studies have shown that more than half of low blood glucose episodes happen during sleep at night. Although this condition is known to have dangerous outcomes, it can be prevented with planning and education. It is important to work with your healthcare provider to create a plan and understand how to manage the condition.

woman sleeping — FreshSplash / Getty Images

Signs and Symptoms

Hypoglycemia is also known as low blood sugar. This happens when the blood sugar levels drop below 70 mg/dL. This is common in people with diabetes but people without diabetes can experience hypoglycemia as well.

When people are awake during the day, they typically know when their blood sugar is low due to symptoms they may experience or if they have a monitor that informs them of their numbers. Some of the symptoms of hypoglycemia are the following:

Mild to moderate

Uncoordinated
Irritable or nervous
Argumentative or combative
Trouble concentrating
Weak
Fast or irregular heartbeat
Shaky or jittery
Sweaty
Hungry
Headachy
Blurred vision
Sleepy or tired
Dizzy or lightheaded
Confused or disoriented
Pale
Changed behavior or personality

Severe

Unable to eat or drink
Seizures or convulsions (jerky movements)
Unconsciousness

Symptoms of nocturnal hypoglycemia

Crying out or having nightmares
Sweating enough to make your pajamas or sheets damp
Feeling tired, irritable, or confused after waking up
Trembling or shaking
Changes in breathing (suddenly breathing fast or slowly)
Racing heartbeat

If a person sleeps with a partner, they may be the first to notice the nighttime symptoms since the person experiencing it is sleeping.

Risk Factors and Causes

Risk factors for hypoglycemia include:

Skipping meals
Delaying meals
Increasing physical activity beyond your normal routine
Not eating enough carbohydrates
Consuming too much alcohol without the proper amount of food
Being sick

Some factors that cause nocturnal hypoglycemia include:

Exercising before bedtime
Drinking alcohol before bed
Skipping meals (typically dinner)
Having infections

It is important to work with your healthcare provider and discuss your specific symptoms and create a proper plan for the best outcome.

Diagnosing Nocturnal Hypoglycemia

Nocturnal hypoglycemia can be difficult to detect because when a person experiences it they are sleeping. A partner or roommate in the company of the person experiencing nocturnal hypoglycemia can help.

Some of the following symptoms can help detect the condition.

Crying out or having nightmares
Sweating enough to make your pajamas or sheets damp
Feeling tired, irritable, or confused after waking up
Trembling or shaking
Changes in breathing (suddenly breathing fast or slowly)
Racing heartbeat

Another way to detect nocturnal hypoglycemia is with a continuous glucose monitor (CGM). A CGM is a device that checks blood glucose levels regularly throughout the day and at night. It will have an alert if the blood glucose is falling fast and an alarm will go off if the blood glucose is too low. This device is loud enough that a person will wake up if nocturnal hypoglycemia occurs.

Does Poor Sleep Affect Blood Sugar?

Sleep is important for overall health, including the regulation of metabolism. Therefore, studies have shown that insufficient sleep and sleep disorders have been identified as risk factors for the development of diabetes.

Preventing Nocturnal Hypoglycemia

There are some ways to prevent nocturnal hypoglycemia. This includes:

Checking blood sugar levels before bed
Using the continuous glucose monitor
Avoiding skipping dinner
Finding an exercise routine and time that is best for your condition
Watching your alcohol intake
Eating according to your plan established by your healthcare provider

Treating Hypoglycemia

If you do have to treat your hypoglycemia to immediately raise your blood sugar levels, use the rule of 15:

Eat 15 grams of carbohydrates (this can include four glucose tablets or four ounces of fruit juice)
Check the blood sugar 15 minutes later

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