What Is Hypoglycemia? Symptoms, Causes, Diagnosis, Treatment, and Prevention

When managing diabetes, you know it’s important to keep your blood sugar steady and in the healthy range that your healthcare team has established for you. Sometimes in diabetes, blood sugar levels may go too high, but letting your levels dip too low — called hypoglycemia — is also dangerous.

Hypoglycemia occurs when glucose dips to 70 milligrams per deciliter (mg/dL) or lower. (1,2)

Both people with type 1 diabetes and type 2 diabetes are at a greater risk for blood sugar fluctuations compared with people without the diseases because their bodies either don’t make enough insulin or can’t use it properly. Insulin is a hormone that ferries glucose to cells and muscles for energy. In general, people with type 1 diabetes don’t make enough insulin, while people with type 2 diabetes still make insulin but have what’s called insulin resistance, where their cells are resistant to the hormone. When there is a relative deficiency of insulin, this causes hyperglycemia, or high blood sugar. (3,4)

If you don’t have diabetes, your body is typically able to regulate your blood sugar levels just fine. But if you have the disease, you’ll need to talk to your doctor about your target range, as everyone’s goal varies.

In the meantime, here’s everything you need to know about hypoglycemia.

The good news is that you can use test strips or a continuous glucose monitor to measure your blood sugar levels. (5) It’s important to know that some people can feel symptoms of low blood glucose even if the blood sugar is normal, called pseudohypoglycemia. On the flip side, some mild cases of low blood sugar may not cause any symptoms at all. This is where regular at-home testing becomes important if you have diabetes, especially if you have type 1 diabetes. (6)

One of the first physical symptoms of hypoglycemia is hunger. At first, you might pass this off as being “hangry” if you have other symptoms like irritability from not eating in a while. But aside from hunger and irritability, other early signs of hypoglycemia may include: (7)

• Shakiness, which is especially noticeable in your hands
• Anxiety
• Blurry vision
• Headaches
• Light-headedness
• Pale skin
• Sleepiness
• Concentration difficulties
• Increased heart rate

More serious cases of hypoglycemia may arise when your blood sugar dips way too low. “People with diabetes are primarily at risk for hypoglycemia due to the medications that are prescribed to help control high blood sugar. There is also a relatively rare condition that causes significant hypoglycemia called an insulinoma,” says Gregory Dodell, MD, assistant clinical professor at the Icahn School of Medicine at Mount Sinai in New York City. An insulinoma is caused by a noncancerous tumor in the pancreas that makes too much insulin. (8)

In more severe or prolonged hypoglycemia, loss of consciousness and seizure are also possible.

For most people with diabetes, hypoglycemia is more complex than simply not getting enough glucose. Your medication may cause low blood sugar, for example.

If you have type 1 diabetes or if you have type 2 diabetes and take insulin to regulate your blood sugar levels, you can experience low blood sugar if you do not take the proper amount of insulin, Dr. Dodell says. This is also noted by the American Diabetes Association. (9)

Other diabetes medication can interfere with insulin production and make your glucose drop, too. Among these are the insulin-increasing drugs for type 2 diabetes called sulfonylureas and their less potent counterparts called meglitinides. (2)

Sometimes hypoglycemia may even occur in your sleep, causing nightmares and sweating. (2) Previous research has also indicated that people with type 1 diabetes may have an increased risk of hypoglycemic-related cardiac arrest during sleep. (10)

For people with type 2 diabetes, it’s possible to experience hypoglycemia after eating a large, carbohydrate-heavy meal due to higher levels of insulin circulating in the body, Dodell adds.

Your risk for hypoglycemia depends on your health and how well you’re managing your blood sugar.

Aside from any possible diabetes medication side effects, your blood sugar levels may decrease as a result of: (6)

• Illnesses
• Drinking alcohol (especially if you drink too much without eating)
• Not eating enough carbohydrates
• Exercising harder than normal
• Skipping regular meals (breakfast, lunch, dinner)

Your doctor will diagnose hypoglycemia based on a physical exam, your health history, your symptoms, and testing of blood glucose. A first step in diagnosis can be to document blood glucose values of less than 70 mg/dL at home when symptoms occur. This may be confirmed with a blood draw. (1)

Timing of hypoglycemia can be important in the diagnosis. Some causes of hypoglycemia are more likely to result in low blood glucose when fasting, while other causes can induce hypoglycemia after meals.

Prognosis of Hypoglycemia

Because hypoglycemia is largely a symptom of another underlying condition, the overall prognosis will vary. If insulin resistance or diabetes is a contributing factor, lifestyle choices and/or medications you’re taking that may contribute to low blood sugar levels will need to be adjusted. (6)

It’s important to catch hypoglycemia in its early stages to prevent possible life-threatening complications. It’s also recommended that you wear a medical bracelet and teach loved ones how to administer glucagon (Glucagen) injections in case of an emergency with extremely low blood sugar and diabetes. (2)

When detected early, hypoglycemia may be reversed within 15 minutes of taking sugar tablets or eating a high-sugar food. However, you may need to repeat the process, in turn increasing the amount of time your hypoglycemia lasts. (6)

If your hypoglycemia is related to diabetes, you will need to monitor your blood glucose regularly for the rest of your life. (3)

Hypoglycemia is largely controlled by preventive measures, such as diet and exercise. If your blood sugar still drops, you can help bring it back up with fast-acting carbohydrates. Depending on the underlying causes of hypoglycemia, you may also need medications, too.

Medication Options

If you’re managing type 1 or type 2 diabetes, you have oral and injectable medications at your disposal. For diabetes, however, many of these medications are designed for the treatment of high blood sugar.

Mild symptoms of low blood sugar may be remedied by fast-acting carbohydrates.

For severe symptoms, such as loss of consciousness, on the other hand, a loved one or medical professional will need to administer a glucagon injection. (2) Another way to administer glucagon is via an inhalable nasal powder, which the Food and Drug Administration approved in 2019 to treat severe hypoglycemia in people ages 4 and older. (11)

Diet Options

If your blood sugar dips too low, you can reach for certain foods to get it back within a safe range.

You need to eat or drink 15 grams (g) worth of carbohydrates once your levels drop to 70 mg/dL or lower. (2) This may involve eating 1 tablespoon (tbsp) of honey, 2 tbsp of raisins, or ½ cup of soda or fruit juice — just be sure these are the versions with real sugar, not artificial sweeteners, so your blood sugar responds accordingly. While you want to reduce sugary drinks in your diet overall, diet and sugar-free drinks will do little to bring your blood glucose up in the event of hypoglycemia.

You can check your blood sugar again after 15 minutes of eating. If it’s still low, the American Diabetes Association recommends repeating the process. (12) If you take glucose tablets, make sure you get 16 g total (usually 4 g each in four total tablets).

To keep your blood sugar levels steady over the long haul, Dodell recommends eating balanced meals of carbs, lean proteins, and healthy fats at short, regular intervals. Contrary to what some influencers and popular diet marketers say, there’s no such thing as a true hypoglycemia diet.

Exercise and Hypoglycemia

Exercise is key for regulating insulin and blood sugar.

If you have high blood sugar, working out can lower it. That’s because your body can naturally take up glucose from insulin more effectively during and after physical activity. (12)

The trick is exercising the right amount — and at the right intensity. Exercising at a harder level than you’re used to can make your blood sugar levels drop quickly. Such effects can last for 24 hours. (2)

Still, you shouldn’t let the fear of hypoglycemia hold you back from exercising. It’s important to focus on more moderate activities, such as walking, bike riding, and swimming. As you get used to working out, gradually increase the time and intensity of your sweat sessions. For someone new to exercise, this could mean increasing your daily walks by a few minutes every week.

To be on the safe side, check your glucose levels beforehand. You may also want to have a meter on hand during and after your workout.

Low blood glucose is a serious condition that needs prompt treatment. In addition to long-term dietary and lifestyle changes, you can help prevent low blood sugar by keeping tabs on your overall health and taking any medications as directed. (6)

It’s also important to collect blood sugar data at home. Your doctor may recommend using a continuous glucose monitor (CGM) in conjunction with a food diary. A CGM can help alert you when your blood sugar levels drop too low, and your food diary can help you identify which foods are helpful. (1,6)

Tracking your numbers on a diabetes app can also help you identify trends in your hypoglycemia (see below for some of our favorites). If apps aren’t your thing, keeping a traditional diabetes journal can work just as well (minus the phone notifications). Write down your meals, as well as your glucose numbers, before and after you eat. You can also keep tabs on your numbers before and after workouts.

Diabetic Alert Dogs Can Help

Not only can dogs deal with low blood sugar like people, but they are also known to help their human companions detect hypoglycemia.

In a 2016 study, researchers studied eight women ages 41 to 51 with type 1 diabetes and found that dogs (in these cases, called diabetic alert dogs) could detect isoprene chemicals, a marker of low blood sugar, on participants’ breath. These results suggest dogs may be able to warn their owners of impending hypoglycemic attacks. (13) Dogs can be trained to detect such episodes.

Left untreated, hypoglycemia may lead to potentially life-threatening complications. Severe hypoglycemia must be treated with an emergency glucagon injection. (2)

Hypoglycemia may contribute to the following complications: (6)

• Dizziness
• Weakness
• Dementia (in older adults)
• Car accidents
• Falls and other injuries

If you have diabetes, it’s important to make sure that overtreating low blood sugar doesn’t cause hyperglycemia. That’s because blood sugar that is repeatedly too high, or blood sugar that dramatically swings from low to high, may play a role in the development of the following complications: (3)

• Sleep apnea
• Heart disease
• Stroke
• Kidney disease
• Eye diseases
• Nerve damage or neuropathy

Repeated cases of hypoglycemia can contribute to the development of a dangerous condition called hypoglycemia unawareness. With this condition, your brain can no longer identify the warning signs of low blood sugar. Your body may also no longer create any noticeable symptoms as a warning. (6)

Hypoglycemia Unawareness

Hypoglycemia unawareness occurs when low blood sugar goes undetected, and people who have frequent low blood sugar, such as those who have type 1 diabetes and individuals who have been living with type 2 diabetes for several years, are at the highest risk. Hypoglycemia unawareness can be dangerous to the brain and lead to symptoms like confusion, weakness, or tingling in the mouth or fingers. (14)

In cases of hypoglycemia unawareness, the risk for diabetic coma, unconsciousness, and convulsions also increases. (14)

Your doctor may have you use a CGM or change your glucose targets if you experience hypoglycemia unawareness. (15)

Because hypoglycemia is largely a symptom of an underlying condition, it’s unclear exactly how common it is in the United States. However, here’s what we do know:

• According to the Centers for Disease Control and Prevention (CDC), 37.3 million people in the United States have diabetes. This is roughly 11.3 percent of the population, and the majority of these cases are type 2 diabetes. (16)
• In the type 2 diabetes sphere, elderly adults are at highest risk for hypoglycemia unawareness. Previous research found that only 1 in 13 older adults with type 2 diabetes were able to correctly identify their symptoms. (17)
• According to CDC data, 242,000 people with diabetes were admitted to the emergency room in 2018 due to hypoglycemia; and of that group, 59 percent were treated and released, but the remaining patients needed to be hospitalized or transferred to other care centers. (21)
  
• Insulin excess is responsible for between 4 and 10 percent of deaths in patients with type 1 diabetes. (18)
• A previous study identified a higher rate of hypoglycemia-related hospital visits in Black American men with type 2 diabetes. (19)

Hypoglycemia is primarily linked to diabetes. Taking insulin or other diabetes medications can make your blood sugar drop to dangerously low levels. (6)

Other related conditions include: (6)

• Kidney disease
• Liver disease, including cirrhosis of the liver or severe hepatitis
• Insulinoma, a type of pancreatic tumor that causes a drop in insulin production
• Pituitary gland tumors
• Adrenal gland disorders
• Alcohol disorders, including binge drinking

Certain medications may also cause hypoglycemia. These include: (1)

• Certain antibiotics, such as sulfonamides (“sulfa drugs”)
• quinine (Qualaquin) for malaria
• Salicylates, such as aspirin (Vazalore)
• Pentamidine for pneumonia

Hypoglycemia in Dogs

While your dog looks out for you, it’s important to return the favor. Animals, including dogs, are also at risk of hypoglycemia. But unlike humans, dogs can’t tell you the signs. It’s important to look for nonverbal cues, such as excessive hunger, anxiety, and restlessness. Your dog may also have muscle tremors. These signs are more prominent after eating or activity. (20) A veterinarian can help detect diabetes, tumors, and other possible causes of low blood glucose in your canine companion.

Favorite Orgs for Essential Hypoglycemia Info

Hypoglycemia Support Foundation

Upon entering this website, you’ll see what sets the Hypoglycemia Support Foundation apart from other organizations: Its sole focus is on topics related to hypoglycemia. This resource may be especially helpful if you have hypoglycemia that is unrelated to diabetes. Be sure to check out the extensive diet resources, as well as multiple ways to get involved, including community awareness projects and conferences.

American Diabetes Association (ADA)

The ADA is a well-known organization dedicated to diabetes research, education, and community. Its website also offers essential resources for hypoglycemia related to diabetes and other underlying causes. Bookmark the ADA for up-to-date tips on how to manage low blood sugar. You can also find online communities to connect with others who may be going through similar struggles.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

The NIDDK is part of the National Institutes of Health, which is a government-funded program in research and education. Aside from offering the latest on diabetes and related conditions, the NIDDK website also has educational articles on hypoglycemia you can peruse. While you’re there, feel free to sign up for emails to receive the latest news from the NIDDK.

Favorite Apps

Blood Glucose Tracker

Blood Glucose Tracker is one among many apps that can help you track your blood sugar levels and identify trends. You can also track your meals and any medications you take. Furthermore, you can set the app to give you reminders for when it’s time to check your sugar levels.

Glucose Buddy

While this app is also focused for people with diabetes, those without this health condition may benefit from the blood sugar tracking tools found on Glucose Buddy. Additionally, you can track the foods you eat, any workouts you complete, and your blood pressure for further insights into how your blood sugar may be affecting your day-to-day health (and vice versa).

For more of our favorite apps for managing diabetes, check out our list.