Hypoglycemia Unawareness:

When You Don’t Know You’re Going Low

Hypoglycemia unawareness, also known as hypo unawareness or impaired awareness of hypoglycemia, is when you don’t experience or recognize the symptoms of low blood sugar. Hypo unawareness is a common complication of diabetes. Around 25 percent of individuals living with type 1 diabetes (T1D) experience it and around 10 to 15 percent of those living with type 2 diabetes (T2D) experience it as well.¹ It’s important to understand what hypo unawareness is, how it happens, and what to do if you develop it because it plays an important role in diabetes management and your overall health and well-being.

What is Hypoglycemia?

Hypoglycemia is low blood sugar. Our bodies use sugar, also known as glucose, from the foods and drinks we consume for fuel.² Hypoglycemia happens when there isn’t enough glucose in the blood to be used for energy. It’s more likely to occur in individuals who manage their blood sugar with insulin.³ This is because insulin helps the cells in the body absorb glucose. When there’s more insulin and not enough glucose coming into the body, it runs out of fuel too quickly.²

Diabetes Canada defines glucose levels below 4.0 mmol/L as hypoglycemia. Dropping below 2.8 mmol/L is considered severe hypoglycemia and requires urgent medical attention.⁴ In general, Diabetes Canada recommends that individuals living with diabetes keep their glucose between 3.9 and 10.0 mmol/L.⁵

Everyone’s experience of hypoglycemia is different. Those experiencing hypo unawareness may no longer experience symptoms at all. Just a handful of the initial low blood sugar symptoms that individuals may experience include:^6,7

• Shaking or sweating
• Having a headache or feeling lightheaded, weak, or drowsy
• Having a fast heartbeat
• Being irritable, nervous, or anxious
• Having difficulty concentrating

Symptoms of worsening hypoglycemia can look like:⁹

• Loss of coordination, slurred speech, or confusion
• Blurry vision or tunnel vision
• Having nightmares (during a nighttime hypo)

Understanding Hypo Unawareness

Hypo unawareness is not a personal failing or a lack of judgment. It’s something that happens to the brain and nervous system as the body experiences hypoglycemic events. Individuals who have lived with diabetes or used insulin for a long time are more likely to experience challenges around feeling hypoglycemia in their bodies.¹ Researchers are still working to determine why hypo unawareness happens and ways to reverse it.⁸ If you’re experiencing hypo unawareness, know that it’s not your fault.

What is the Most Common Cause of Hypoglycemia Unawareness?

Hypo unawareness happens as the body gets used to experiencing frequent or severe hypoglycemic events over time. When your glucose levels go low, the body sends signals in the form of symptoms—such as shaking, sweating, or feeling irritable—to alert you that something is wrong and you should take action. However, when individuals repeatedly experience hypoglycemia, the body builds up a tolerance and doesn’t send out these signals right away. As time goes on, the body might stop sending signals entirely, which means that you won’t be able to feel when you’re experiencing a severe low.^1,4

Nocturnal hypoglycemia, or experiencing hypos while you sleep, can increase the risk of developing hypo unawareness.⁴ When you’re asleep, your body is not as responsive to hypoglycemia, so you’re more likely to sleep through a low.⁴ Severe hypoglycemia and lows lasting more than four hours are more common at night.⁴ The more often an individual experiences nighttime hypos, the less sensitive their body will be to them, which further contributes to hypo unawareness.4 Alcohol also reduces the body’s sensitivity to hypoglycemia, which can lead to more frequent hypos and, in turn, increased hypo unawareness.⁴

Can You Prevent or Reverse Hypo Unawareness?

Glucose management is key to reducing the risk of developing hypo unawareness and improving sensitivity to symptoms.4,8 Avoiding hypoglycemia for at least two days and up to three months or more is associated with an improvement in individuals’ ability to feel the signs of a hypo.4 Researchers are exploring whether high-intensity exercise could play a role in increasing hypo sensitivity. It’s important to talk to your doctor and diabetes care team if you’re having challenges with hypoglycemia and hypo unawareness. They can help you create a personalized diabetes care plan to help you control your glucose levels and avoid hypos as often as possible.

Preventing Hypoglycemia

You can work on preventing hypoglycemia by managing your glucose levels. There are many factors that can affect your glucose beyond just food and exercise. You and your doctor will work together to come up with a diabetes management plan that will help you spend more time in your target glucose range and avoid hypoglycemia. If you’re using insulin therapy, it’s a good idea to understand how different types of insulin work. Be sure to talk to your doctor and diabetes care team about your insulin so that you can create dosing routines that work best for you.

It’s also important to talk to your doctor about how to treat hypoglycemia when it happens. Treating a hypo in the moment typically requires you to consume glucose to boost your levels back up to a healthy range. Diabetes Canada recommends that individuals get 15 grams of carbohydrates—such as sugar, honey, juice, or candy—to treat mild-to-moderate hypoglycemia.^3,4

Getting Ahead of Low Glucose with Dexcom CGM

Experiencing hypo unawareness can be stressful and even scary. Continuous glucose monitoring (CGM) systems can help you be proactive about preventing hypoglycemia even if you’re experiencing hypo unawareness. CGM systems like Dexcom CGM Systems work by taking glucose readings continuously and sending them to a display device, such as a compatible smart device or hand-held receiver.* This can provide a real-time view into where your glucose has been, and where it’s going, so you can worry a little less about knowing when you’re low.

Studies show that using Dexcom CGM Systems helps individuals living with diabetes reduce hypoglycemia and spend more time in their target glucose range. ^10-15 Dexcom CGM Systems are also proven to help those living with T1D who experience hypo unawareness reduce the frequency of hypos.¹⁵ Diabetes Canada guidelines state that those experiencing hypo unawareness should use CGM to support their glucose management.⁴ Dexcom CGM Systems, including Dexcom G6 and Dexcom G7, have several features that can help you be in the know about low glucose—even before it happens.

Predictive Urgent Low Soon Alert

Dexcom CGM Systems are the only CGM systems that can provide a predictive alert that can let you know up to 20 minutes before you’re likely to experience a serious low under 3.1 mmol/L. This can enable you to take action to prevent hypoglycemia before it happens. You can also use this alert during the night to get some extra peace of mind around going low while you’re asleep. Using the predictive alert is associated with significant reductions in hypoglycemia.¹⁷

Urgent Low Alert

Dexcom G6 and Dexcom G7 also have a built-in Urgent Low Alert that can notify you the moment your glucose drops below 3.1 mmol/L. You can’t turn the Urgent Low Alert off, which can give you greater confidence that you’ll be able to catch a low when it happens, even if you can’t feel it.

Remote Monitoring

With the Dexcom Follow app, parents and caregivers can keep an eye on glucose levels remotely and receive glucose alerts on their compatible smart device as long as they have an internet connection.^† This can empower them to better support children and individuals dealing with hypo unawareness by providing greater visibility into what’s going on with their glucose, even if they aren’t in the same room. Using the Dexcom Follow app has been shown to help individuals living with T1D decrease the frequency of hypoglycemia and feel more confident about managing hypos. It has also been shown to help those living with T1D get a better night’s sleep, reduce diabetes-related stress, and increase their overall sense of well-being.¹¹

Find Out Which Dexcom CGM is Right for You

Dexcom CGM Systems can help you get greater insight into what’s going on with your glucose and can empower you to avoid and manage hypoglycemia, even if you experience hypo unawareness. Talk to your doctor about whether using a Dexcom G6 or Dexcom G7 CGM System fits into your diabetes treatment plan.

• Compare Dexcom G6 and Dexcom G7

* For a list of compatible smart devices visit www.dexcom.com/compatibility
† Following requires the Dexcom Follow app and an internet connection. Followers should always confirm readings on the Dexcom G6 or Dexcom G7 app before making diabetes treatment decisions.

1 How Hypoglycemia Unawareness Affects People with Diabetes. National Institute of Diabetes and Digestive and Kidney Diseases. April 5, 2023. Accessed December 16, 2023. https://www.niddk.nih.gov/health-information/professionals/diabetes-discoveries-practice/how-hypoglycemia-unawareness-affects-people-with-diabetes
2 Hantzidiamantis PJ, et. al. Physiology, Glucose. StatPearls Publishing. Updated September 19, 2022. Accessed December 16, 2023. https://www.ncbi.nlm.nih.gov/books/NBK545201/
3 Lega IC, et al. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Hypoglycemia in Adults. Can J Diabetes. 2023;47(7):548-559. doi:10.1016/j.jcjd.2023.08.003
4 Yale JF, et al. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Hypoglycemia. Can J Diabetes. 2018;42 Suppl 1:S104-S108. doi:10.1016/j.jcjd.2017.10.010
5 Imran AS, et. al. Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Targets for Glycemic Control. Can J Diabetes. 2018:42(S42–S46). doi: 10.1016/j.jcjd.2017.10.030
6 Lows and highs of blood sugar. Diabetes Canada. Updated December 16, 2023. Accessed December 16, 2023. https://www.diabetes.org.uk/node/14966
7 Hypoglycemia: Symptoms and Causes. Mayo Clinic. Reviewed November 18, 2023. Accessed December 16, 2023. https://www.mayoclinic.org/diseases-conditions/hypoglycemia/symptoms-causes/syc-20373685
8 Hypo unawareness. Diabetes UK. Accessed December 16, 2023. https://www.diabetes.org.uk/guide-to-diabetes/complications/hypos/hypo-unawareness
9 Can exercise bring back hypo awareness? Diabetes UK. October 13, 2017. Accessed December 16, 2023. https://www.diabetes.org.uk/node/14966
10 Beck RW, et al. Effect of Continuous Glucose Monitoring on Glycemic Control in Adults With Type 1 Diabetes Using Insulin Injections: The DIAMOND Randomized Clinical Trial. JAMA. 2017;317(4):371-378. doi:10.1001/jama.2016.19975
11 Beck RW, et al. Continuous Glucose Monitoring Versus Usual Care in Patients With Type 2 Diabetes Receiving Multiple Daily Insulin Injections: A Randomized Trial. Ann Intern Med. 2017;167(6):365-374. doi:10.7326/M16-2855
12 Martens T, et al. Effect of Continuous Glucose Monitoring on Glycemic Control in Patients With Type 2 Diabetes Treated With Basal Insulin: A Randomized Clinical Trial. JAMA. 2021;325(22):2262-2272. doi:10.1001/jama.2021.7444
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16 Cheng AYY, et al. Diabetes Canada 2018 Clinical Practice Guidelines for the Prevention and Management of Diabetes in Canada: Blood Glucose Monitoring in Adults and Children with Diabetes: Update 2021. Can J Diabetes. 2021;45(7):580-587. doi:10.1016/j.jcjd.2021.07.003
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