Your diabetes care team can help address low blood sugars that develop while you’re asleep. They may suggest insulin and eating adjustments, or technology to alert you overnight.

Nocturnal hypoglycemia is the medical term for low blood sugar that happens while you sleep.

While people with diabetes can keep better tabs on their blood sugar levels when awake, that task becomes more challenging when it’s time to sleep. This means you may not wake up to notice low blood sugars, leading to them not being treated quickly and becoming medical emergencies.

Several key strategies can help you treat and prevent nocturnal hypoglycemia. Knowing the causes and taking action to keep blood sugar levels from dropping too low are effective ways to reduce the risk.

The American Diabetes Association (ADA) defines low blood sugar as below 70 milligrams per deciliter (mg/dL).

Severe hypoglycemia is when levels drop below 55 mg/dL.

Research shows that more than half of severe hypoglycemia episodes happen overnight.

Several factors make nocturnal hypoglycemia more likely, including:

  • lower A1C levels (a measure of your average blood sugar level over a few months)
  • medium- or high intensity exercise during the day, prior to the nocturnal hypoglycemic event
  • low bedtime blood glucose level
  • people who don’t feel low symptoms, known as hypo unawareness
  • older adults
  • young children

Many other things can lead to hypoglycemia no matter the time of day or night, but some of them may be more challenging to address overnight and when sleeping.

For those with hypo unawareness and can’t feel their symptoms of low blood sugar as much even when they’re awake, the risk of hypos can be 6 times greater than those without unawareness.

This can include alcohol consumption, which can lead to lower blood sugars several hours after the last drink.

For those who experience hypoglycemia when sleeping, this may be the same as how they address these when they aren’t asleep.

Diabetes devices including CGM technology

Modern diabetes technology has improved life with this condition, including how people are able to manage hypoglycemia when they’re sleeping.

Some people with diabetes may use continuous glucose monitoring (CGM) to manage and prevent low blood sugar.

These devices are worn on the skin, with a small needle inserted just under the top layer of skin to monitor glucose levels. Every few minutes, the CGM sends a blood sugar reading to a smartphone app or separate receiver, and many can alert people to low or high glucose levels.

CGMs can benefit people on insulin in the context of nocturnal hypoglycemia, including those with both type 1 and type 2 diabetes as well as gestational diabetes during pregnancy.

Insulin pumps

This technology replaces syringes and vials, or prefilled insulin pen needles.

These wearable devices are filled with enough insulin to last 2 to 4 days, and through a small cannula inserted just under the top layer of skin, they constantly deliver insulin throughout the day, and at times, you tell them to.

For example, you have a set amount delivered in the background to keep your blood sugars stable during the day and night. For correction doses, when your sugar rises too high or when you eat or drink foods that raise blood sugar, you also take a calculated amount at that time.

Modern insulin pumps are often tied to smartphone apps and have smart algorithms, meaning they can connect to CGMs to monitor glucose data and automatically insulin amounts based on your changing needs.

With this technology, you can adjust your insulin dose settings to accommodate nighttime blood sugars while you sleep. For pumps that automatically adjust insulin levels, this is another level of security to guard against nocturnal hypoglycemia.

Eating before bedtime

You may eat a small snack before going to bed, to help manage any low blood sugars while you’re sleeping.

What you eat may depend on your own diabetes management and advice from your care team. But some clinicians suggest a peanut butter on a slice of toast and a cup of milk, or something similar.

The combination of carbs with protein is meant to help sustain you throughout the night.

Limiting evening alcohol

Alcohol affects glucose levels long after you’ve had the drink.

Certain drinks may have more carbs or be sweetened with mixers, which can be misleading because they can initially cause higher blood sugars. This can cause people to take more insulin to correct that higher level.

But over time, alcohol drops blood sugar because it interferes with the liver naturally releasing stored glucose into your blood while the organ processes the alcohol for your kidneys to flush out.

As a result, your blood sugar can drop.

This may take as long as 7 to 12 hours after finishing the last drink.

You might consider snacking while you drink, or before going to sleep if you’ve consumed alcohol.

Monitoring after exercise

Exercise also affects blood sugar levels.

While some physical activity may lower your blood sugars more quickly afterward, certain intense or long-endurance activities may have an effect many hours later — including when you’re asleep.

If you’ve been active, you can monitor your blood sugars before going to sleep, and you can also eat before bed to help counter any drops when you’re asleep.

you should take the same actions as you do to manage hypoglycemia in the daytime: Eat a quick-acting carbohydrate and a slow-acting carbohydrate.

Emergency glucagon

This type of treatment involves an emergency kind of glucagon, a product designed to treat severe hypoglycemia.

While this has historically been used as an emergency treatment for those who can’t self-treat low blood sugars, some people with diabetes keep it on hand to treat severe lows that they can still manage without assistance.

This is a prescription item that you can get from a local pharmacy.

If you’re caring for someone who experiences low blood sugar while sleeping, you can take these steps to help manage that hypoglycemia.

  1. Wake them up and gauge their symptoms. If they wake up and can sit by themselves, give them fast-acting glucose, like juice or hard candy.
  2. After blood sugars rise, have them eat something more substantial, such as cheese or peanut butter and crackers, a sandwich, or fruit with fiber and protein, like a banana.
  3. Monitor blood sugars over the next couple of hours to be safe and ensure they don’t drop too low again.

If that person doesn’t wake up or is unable to treat themselves, you may need to take more action.

This could include using an emergency glucagon injection to quickly raise their blood sugar levels.

Once the glucagon takes effect and you notice it is working, have your loved one eat something more and test their blood sugar every couple of hours.

Severe hypoglycemia can be a medical emergency

You may need to call 911 or emergency medical help if you can’t wake someone up, or help them treat a severe low blood sugar.

These can become dangerous, life-threatening situations if a hypo isn’t treated quickly.

To prevent nocturnal hypoglycemia on an ongoing, long-term basis, consult a healthcare professional. You should also:

  • check blood glucose levels before going to bed
  • stick to regular meals and snacks at routine times
  • adjust insulin dose if necessary before going to sleep.

It’s important to contact your doctor once you know or suspect you have experienced nocturnal hypoglycemia. You and your doctor can then discuss your diabetes management plan.

They may also help address fear of hypoglycemia, a phenomenon that can cause some people with diabetes to keep their glucose levels higher when they sleep to avoid severe low blood sugars.

Nocturnal hypoglycemia is low blood sugar that occurs during sleep. To reduce the risk, monitor blood sugar closely and maintain an effective routine of healthy eating and insulin doses.

If you experience nocturnal hypoglycemia, work with your doctor to develop a robust management plan to prevent it from happening in the future.