Hypoglycemia Unawareness: Symptoms, Causes, and Treatment

The primary goal of managing diabetes is keeping blood sugar levels in a target range. 

You don’t want them too high or too low. 

You can’t always feel when blood sugar levels are high (which is why diabetes can go undiagnosed for a long time), but you’re more likely to know when you’re experiencing a low. 

However, what happens if you can’t recognize the symptoms of low blood sugar? 

This condition is called hypoglycemia unawareness, and we’ll explain what it is and how to prevent it in this article.

What is hypoglycemia?

Hypoglycemia is the medical term for low blood sugar. Normal blood sugar ranges between 70-140 milligrams per deciliter (mg/dL). If it falls below 70 mg/dL, it’s considered low blood sugar.

Your body normally works to keep your blood sugar within the normal range by releasing insulin to lower blood sugar and breaking down glycogen (sugar stored in your liver) to raise blood sugar. Despite this feature of your autonomic nervous system, there are times when blood sugar levels go too high and too low.

There are different levels of hypoglycemia, which correlate with how severely low the blood sugar levels are.

• Level 1 (mild) hypoglycemia. Blood glucose is less than 70 mg/dL but is 54 mg/dL or higher.
  
• Level 2 (moderate) hypoglycemia. Blood glucose is less than 54 mg/dL.
  
• Level 3 (severe) hypoglycemia. A person cannot function because of mental or physical changes, and they need help from another person. In this case, blood glucose is often below 40 mg/dL.

Hypoglycemia occurs for many reasons. One of the most common causes of hypoglycemia is taking too much medication that lowers blood sugar levels in people with diabetes. 

Insulin comes with the greatest risk of hypoglycemia among diabetes medications, along with sulfonylureas.

Hypoglycemia can also occur from not eating enough carbohydrates, especially if you’re also taking blood sugar-lowering medications. Exercise can also cause low blood sugar because it uses up stored sugar in your liver called glycogen.

What are the symptoms of hypoglycemia?

There are several symptoms of hypoglycemia to watch out for. If you take a blood sugar-lowering medication, especially insulin, you and your support team (family, friends, etc.) should familiarize yourself with the symptoms of hypoglycemia so you can quickly treat it.

Some of the most common symptoms of hypoglycemia are:

• Feeling shaky and/or dizzy
• Rapid and/or irregular heartbeat
• Pale skin
• Fatigue
• Tingling or numbness of the lips, tongue, or cheek
• Sweating
• Hunger
• Feeling irritable or moody
• Feeling anxious or nervous
• Headache

You might not always notice hypoglycemia symptoms, especially at nighttime. Low blood sugar at night is called nocturnal hypoglycemia. This can be even more dangerous because you’re less likely to notice the symptoms. 

Signs of nocturnal hypoglycemia include:

• Damp sheets or nightclothes from sweating due to low blood sugar
• Nightmares
• Feeling tired, irritable, or confused after waking up

If hypoglycemia isn’t corrected, it can become an emergency that warrants prompt medical treatment. 

Signs and symptoms of severe hypoglycemia include:

• Clumsiness or jerky movements
• Muscle weakness
• Slurred speech or difficulty speaking
• Blurred vision or double vision
• Drowsiness
• Confusion
• Convulsions or seizures
• Unconsciousness/fainting
• Coma

What is hypoglycemia unawareness?

Hypoglycemia symptoms result from your adrenal glands (located on top of the kidneys) releasing both epinephrine and cortisol in response to hypoglycemia. These stress hormones are responsible for the symptoms of low blood sugar.

Some people don’t notice the symptoms of low blood sugar. This condition is called hypoglycemia unawareness, and it increases the risk of developing severe hypoglycemia or complications from hypoglycemia, like falling.

Do I have hypoglycemia unawareness?

You might have hypoglycemia unawareness if your blood sugar is low when checked, but you didn’t notice any hypoglycemia symptoms. If you don’t develop symptoms of low blood sugar until it’s severely low, you might also have hypoglycemia unawareness.

One of the best ways to determine if you have hypoglycemia unawareness is to use a continuous glucose monitor (CGM). This device measures your blood glucose levels every few minutes. 

You can set an alarm on the CGM to notify you when your blood sugar levels fall below a set threshold. If the alarm sounds and you don’t have any physical symptoms, that’s a sign of hypoglycemia unawareness. 

Why is hypoglycemia unawareness dangerous?

Hypoglycemia unawareness is dangerous because your body cannot sense that your blood sugar levels are falling. Without experiencing these symptoms, you won’t be able to correct the low blood sugar promptly. This then increases your chance of having severe low blood sugar and related complications.

Severe low blood sugar can cause clumsiness, dizziness, and fainting. If you have hypoglycemia unawareness, you might develop these symptoms at dangerous times, like while driving or operating machinery, which could cause a serious accident.

When it’s untreated, severe hypoglycemia can lead to coma and death.

What causes hypoglycemia unawareness?

The mechanism behind hypoglycemia unawareness isn’t very clear. One of the potential causes is impaired epinephrine secretion. Epinephrine is one of the hormones that help you feel symptoms of low blood sugar. Without enough epinephrine, you might develop hypoglycemia unawareness. This is more common in people with type 1 diabetes.

While the exact physiological mechanisms aren’t as clear, there are several known risk factors for developing hypoglycemia unawareness, which we’ll cover next.

What are the risk factors for developing hypoglycemia unawareness?

Having diabetes for a long time

Having diabetes for a long time is one of the risk factors for hypoglycemia unawareness. If you’ve had diabetes for many years (especially if you have type 1, which tends to show up during childhood and adolescence), you’ve probably experienced low blood sugar many times. This can dull your body’s ability to recognize the symptoms.

According to a study, around half the people who were on insulin for over 20 years (like those with type 1 diabetes who must inject insulin several times per day) developed an inability to detect hypoglycemia.

Having type 1 diabetes 

People with type 1 diabetes experience hypoglycemia unawareness more than those with type 2 diabetes. Around 40% of people with type 1 diabetes have hypoglycemia unawareness.

Frequent episodes of low blood sugar

Having repeated episodes of low blood sugar seems to dull your body’s response to hypoglycemia. This means you won’t be alerted to the low blood sugar as strongly as someone without hypoglycemia unawareness.

Age

People over 65 tend to have more hypoglycemia unawareness compared to younger patients. Part of the reason is from normal cognitive slowing with age, which can interfere with your ability to perceive hypoglycemia symptoms.

The risk of hypoglycemia unawareness and increased risk of falls in older people is one reason why many healthcare providers set less strict blood sugar goals for older patients with diabetes.

Nocturnal hypoglycemia

Low blood sugar while you’re sleeping can decrease your hypoglycemia awareness since you’re unaware of it.

Taking beta-blockers

Beta-blockers are a type of medication used to treat heart arrhythmias and high blood pressure. Beta-blockers block the impact of stress hormones (like epinephrine/adrenaline) on increasing your heart rate, which slows your heart rate. 

An increased heart rate is one symptom of low blood sugar (along with palpitations), which beta-blockers can mask.

Can you reverse hypoglycemia unawareness?

The good news is that improving your ability to sense hypoglycemia is possible. The best way to reverse hypoglycemia unawareness is to avoid having low blood sugar. The longer you go without having a low, the more likely you’ll be to sense when you have low blood sugar.

Setting higher blood sugar goals (to avoid having low blood sugar) for 7-21 days can be enough to help improve hypoglycemia sensitivity.

Temporarily setting the target blood sugar range higher than it was can help “reset” your sensitivity to hypoglycemia symptoms. Depending on the frequency and severity of hypoglycemic events, some healthcare providers might recommend permanently loosening the strictness of blood sugar targets, especially in older people.

Getting your hypoglycemia awareness back

If you experience hypoglycemia unawareness, there are some simple tips you can follow to help get your hypoglycemia awareness back.

Adjust your medications to prevent hypoglycemia

Discuss your medication regimen with your healthcare team and see if you can adjust it to reduce the risk of low blood sugar. You might be a candidate for some of the newer long-acting insulins, which have a lower risk of hypoglycemia.

Check your blood sugar levels often

If you can’t perceive low blood sugar symptoms, then you should check your blood sugar to determine when you’re getting low blood sugar levels. Once you know when you’re most likely to get hypoglycemia, you can better adjust your lifestyle and medication regimen to help prevent it.

Consider getting a continuous glucose monitor

Continuous glucose monitors can alert you when your blood sugar level is falling if your body isn’t able to tell you. Knowing when you’re experiencing hypoglycemia gives you useful information that can help you work to prevent hypoglycemia and improve hypoglycemia unawareness.

Insurance companies might cover a continuous glucose monitor, especially if your healthcare provider writes a letter documenting your history of hypoglycemia and/or hypoglycemia unawareness.

Preventing low blood sugar

Preventing hypoglycemia is the ideal route to avoid hypoglycemia unawareness. While it isn’t always possible to eliminate bouts of low blood sugar, you can prepare yourself with the following tips.

Take medications as prescribed.

Taking insulin is one of the biggest risk factors for developing low blood sugar. Never increase your insulin dose (or other diabetes medication dose) unless your healthcare team recommends it. 

If you take insulin on a sliding scale (the dose depends on your blood sugar), you must check your blood sugar to know which dose to inject. For example, some people might be on a sliding scale where they inject 5 units if their blood sugar is above 150 mg/dL before a meal. If you don’t check your blood sugar first then you might inject too much or too little.

It’s ideal to check your blood sugar before administering fast-acting insulin, which quickly lowers your blood sugar level. You might not need to inject fast-acting insulin if your blood sugar is low enough.

Be ready to treat low blood sugar.

You can’t always prevent low blood sugar, but being ready to treat it can help prevent it from becoming a severe case of hypoglycemia.

You can treat mild low blood sugar with things like fruit juice, glucose tablets, sports gels, and hard candies. If you’re prone to low blood sugar or take insulin, keep these foods and drinks on hand at home, in your car, at work, and while out exercising. 

More severe low blood sugar is treated with a glucagon injection, which helps your body release stored sugar (glycogen) to raise your blood sugar levels. You can get a prescription for a glucagon injection if your healthcare provider thinks you’re a good candidate.

Eat carbohydrates consistently.

Carbohydrates are a type of nutrient that raises blood glucose levels. If you don’t eat enough carbohydrates throughout the day, you might experience low blood sugar, especially if you take insulin and/or exercise.

Plan snacks around exercise.

When you start to exercise, your body uses up glycogen to help fuel your cells as they take up sugar for energy. You’re more likely to develop low blood sugar if you exercise for long periods (over one hour), and after exercise is completed. 

If you’re prone to low blood sugar, be sure to eat a snack containing carbohydrates before exercising. It’s a good idea to have carbs on hand during exercise if needed, as well as for a post-workout snack to help prevent post-exercise hypoglycemia. 

Checking your blood sugar before and after exercise (or using a continuous glucose monitor) will help you determine how your body responds to exercise.

Conclusion

Hypoglycemia unawareness occurs when your body cannot recognize the symptoms of low blood sugar. You’re more likely to experience hypoglycemia unawareness if you’ve had diabetes for a long time, have type 1 diabetes, have a history of frequent low blood sugar episodes, and/or are older.

The best way to improve hypoglycemia awareness is to avoid low blood sugar. You can do this with more frequent blood sugar monitoring and by reducing the strictness of blood sugar targets.

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