Hypoglycemia Symptoms

Why a Short List Is Not Enough

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Hypoglycemia Symptoms

Hypoglycemia is a common side effect of using insulin, and it can also occur in people who take pills that cause the pancreas to release more insulin. Pills that have this effect include the oral drugs chlorpropamide (brand name Diabinese), glyburide (DiaBeta, Glynase, and Micronase), glipizide (Glucotrol, Glucotrol XL), glimepiride (Amaryl), combination drugs that contain glyburide, glipizide, or glimepiride (such as Glucovance, Metaglip, Avandaryl, and Duetact), repaglinide (Prandin), combination drugs that contain repaglinide (Prandimet), and nateglinide (Starlix). It is therefore important that anyone who uses one of these drugs know what causes hypoglycemia, how to prevent it, how to recognize it, and how to treat it.

Often, however, the most education a person receives on the signs and symptoms of hypoglycemia is a handout listing its 10 most common symptoms. This is particularly true for adults. But, as any longtime user of insulin will tell you, such a list does not go far enough in describing how those common symptoms can feel, and it misses some important, albeit not-so-common, symptoms of hypoglycemia.

This article attempts to fill in some of the blanks by describing what those common symptoms really feel like — in a variety of situations, including driving and sleeping — and by describing some less common symptoms. Once you (and your friends, coworkers, and family members) are better equipped to recognize hypoglycemia, you will be able treat low blood glucose faster and avert more severe hypoglycemia and its sometimes serious consequences.

What is hypoglycemia

Low blood glucose, or hypoglycemia, is a condition in which the brain does not have enough glucose to carry out its many functions. In a person with diabetes, it most often results when there is an imbalance in food, insulin, and exercise. In other words, eating raises blood glucose level. Insulin (whether injected or secreted by the pancreas) lowers blood glucose level. Exercise usually lowers blood glucose level (unless there is not enough insulin circulating in the bloodstream, in which case it may raise it). Hypoglycemia results if not enough food is eaten for the amount of insulin present and exercise done.

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When a person’s blood glucose level begins to drop, his body starts a series of reactions intended to raise its blood glucose level. Hormones are produced that cause the release of stored glucose from the liver. These hormones also produce some of the symptoms typically associated with hypoglycemia, such as trembling. If the body cannot reverse the low blood glucose on its own (which can happen if the liver’s supply of stored glucose has been depleted by, say, vigorous exercise) and the person does not recognize the symptoms of low blood glucose and does not consume some carbohydrate, the blood glucose level will drop further. If it goes low enough, a person may become confused or even pass out.

Health-care providers often recommend treating for hypoglycemia if blood glucose is below 70 mg/dl. (For children and elderly people, however, the recommended treatment level may be higher.) Treatment generally involves consuming 15 grams of carbohydrate (the amount in 1/2 cup fruit juice or regular soft drink, 3–4 glucose tablets, 1 tablespoon sugar, or 6–8 Life Savers), waiting about 15 minutes, then checking your blood glucose level with your meter to see if it has risen to a safe level. Some experts also recommend checking blood glucose levels again an hour after the last treatment to see whether additional food is necessary.

Hypoglycemia that you can treat yourself is usually referred to as mild hypoglycemia. If others have to assist you in obtaining and consuming a source of carbohydrate, you would generally be considered to have moderate hypoglycemia. In moderate hypoglycemia, your ability to communicate, pick an appropriate food, or realize that you should do something to raise your blood glucose level may be impaired. Severe hypoglycemia occurs when you have lost consciousness, are having a seizure, or cannot be awakened. To revive you, someone must give you an injection of glucagon, a hormone that stimulates the release of glycogen, a form of stored glucose, from the liver, or emergency services must be called to give you glucose intravenously.

Common symptoms explained

Given the potential consequences of severe hypoglycemia, it’s worth doing your best to avert it by treating mild hypoglycemia as quickly as possible. In addition, the earlier you treat mild hypoglycemia, the faster your symptoms will go away. The following are some common signs and symptoms of hypoglycemia. Just because they’re common, however, doesn’t mean that everyone experiences them. You may have your own, unique indicators of hypoglycemia that don’t appear on this list. In addition, your experience of a common symptom may be somewhat different from someone else’s, or it may be different from what you might have expected. That’s why it’s important to pay attention to any feeling, sensation, emotion, or behavior that might be attributable to hypoglycemia.


A common early symptom of hypoglycemia, shaking does not refer to the full-body shakes of someone having a seizure but instead to a more subtle trembling that may initially be sensed by the person experiencing it without being visible to an observer. It may progress to fine tremors of the fingers so that if you are trying to perform fine motor tasks with your hands, such as writing or threading a needle, you may notice that the task is more difficult. If you are not using your hands, however, you may not notice any trembling.


Another common symptom of the early stages of hypoglycemia, sweating typically occurs all over the body — not just in the armpits — and can progress from mild to drenching. Many people notice the sweating on their face first. You may also feel warmer than usual at first but have chills later. While in some situations you may be keenly aware that your sweating is unusual, there are others in which you may not realize you’re sweating because of hypoglycemia. For example, you would expect to sweat during exercise or while outside on a hot day. If sweating occurred while swimming, taking a shower, or sleeping, you might not even realize you were sweating.

For some people who take beta-blockers, a type of blood pressure medicine, sweating may be the only early symptom of hypoglycemia, because beta-blockers can prevent the body from shaking or having other hypoglycemia symptoms such as a fast heartbeat.

Fast heartbeat

Many things in addition to hypoglycemia can cause a fast heartbeat, including excitement, stress, exercise, or ketones associated with high blood glucose. This can make it harder to notice fast heartbeat as a potential sign of hypoglycemia, but if you are having a fast heartbeat when there is no apparent reason for this to occur, you should check your blood glucose level.

Looking pale

You or those around you may notice that you are paler than usual during hypoglycemia.


Hunger is a useful symptom of hypoglycemia since it usually leads a person to eat and consequently raise his blood glucose level. However, you may be in the habit of ignoring the initial symptoms of hunger at work or school if you’re in a meeting, engrossed in studying, or attending a lecture. This is a dangerous habit to have, because the longer you ignore hunger, the hungrier you get and the more likely you are to overeat when you finally eat. In addition, if you wait until you have moderate hypoglycemia, your judgment may be affected such that you eat the first thing you find, whether or not it will quickly raise your blood glucose level.

Weakness and fatigue

These symptoms are directly related to your body not having enough energy (glucose) for both physical and mental needs. It may be tempting to take a nap when you feel weak and tired, but it’s important to monitor your blood glucose level if you feel this way at a time of day when you are not usually tired. If hypoglycemia is causing your feeling of fatigue, your blood glucose level may go even lower during your nap, and you are unlikely to be able to detect other symptoms of hypoglycemia while asleep.


Having a headache often signals that you had hypoglycemia earlier in the day or have had it for some time. For example, if you wake up with a headache or leave a movie theater with a headache, you may have been hypoglycemic for some time. If the headache is severe enough, you may have nausea. You should treat yourself with carbohydrate and plan to monitor more frequently for the rest of the day. If the hypoglycemia has lasted a long time, the body’s stored sugar may have been used up, and you are more prone to repeat episodes of hypoglycemia that day.

Impaired vision

Double vision and tunnel vision are two types of visual disturbances that may occur with hypoglycemia. Like headache, impaired vision also often signals that your blood glucose has been low for quite some time. Your brain routinely takes two pictures from two eyes and formulates the pictures into a single image. When your brain does not have enough glucose, the brain loses the ability to coordinate vision. You may see fine with one eye closed, but quick action is needed to prevent the confused state that will follow if you don’t raise your blood glucose level.

Enlarged pupils can also be a symptom of hypoglycemia, but you are unlikely to notice them unless you’re looking in a mirror or someone else takes a close look at your eyes. If you are becoming hypoglycemic while reading, you may notice that you cannot find the correct line or that you see fewer words with each glance.

Difficulty communicating

Difficulties with communication can range from not being able to remember a word, to speaking in a monotone, to only responding in simple words such as “yes” or “no.” Some people describe feeling that the words they want to use are just out of their reach.

Difficulty absorbing new information

Without adequate glucose, your brain has trouble taking in new information. If you find yourself reading the same paragraph over and over or listening to someone speak then realizing you missed what was said, perhaps because you were daydreaming, you may have hypoglycemia.


Dizziness is another symptom that occurs after a person has been hypoglycemic for some time. You may have trouble walking a straight line or changing body positions. This is one of many symptoms of hypoglycemia that may be misinterpreted as drunkenness. If strangers or the police find you swerving while walking, medical identification in the form of a bracelet, necklace, or wallet card may save you from a misunderstanding and get you the treatment needed to stave off severe hypoglycemia.

Numbness or tingling

Numbness or tingling in the face or hands may be symptoms of hypoglycemia. Sometimes the numbness is first noticed in one spot, such as the upper lip, then it spreads across the face.

Unusual behavior

Anxious, giddy, confused, and irritable behaviors are important symptoms for friends, coworkers, and family members to learn about. These symptoms may occur when you can no longer judge that you are in danger. Your blood glucose may be so low that you no longer recognize family members or authority figures such as the police. You may argue, cry, yell, or fight.

It can be difficult to help a person who has reached this stage. Often, a person in this stage of hypoglycemia wants to perform a particular task and finds that a “stranger” (the person trying to help) is keeping him from performing that task by trying to get him to consume some carbohydrate.

It may help to talk over the possibility of this happening with your friends, coworkers, and family members before it happens and to brief them on what to do if it does. You might ask your potential helpers to remain calm, to refrain from raising their voices (which can feel threatening), and to place a container of juice or some glucose tablets in your hand or on the table or desk in front of you. Remind them that you may not recognize them when you’re in an agitated or confused state and that you may say potentially hurtful things you don’t mean.

Typically, a person passes from an agitated stage to a more docile stage, when it may be easier to get him to drink juice or to eat something. But the docile stage precedes the passing out stage, leaving little room for comfort. Even though dealing with an agitated person is difficult, it is better to at least try to get him to eat or drink than to simply wait until his blood glucose level drops even lower. Keep in mind that it will take a while for a person’s blood glucose level to rise and that anyone who has needed assistance treating hypoglycemia should not be left alone until his blood glucose is in a safe range and he shows signs of good judgment.

Hypoglycemia while driving

For obvious reasons, it is important for people with diabetes to recognize symptoms of hypoglycemia while driving and to pull over to treat it. However, two common early symptoms of hypoglycemia, shaking and sweating, are often not noticed while driving. Why? If you are gripping the steering wheel, you may not notice fine tremors in your fingers, and if you are driving in hot weather, you may assume that sweating is due to the weather.

One way to lower your chances of experiencing low blood glucose while driving is to establish a minimum safe blood glucose level for driving with the help of your health-care provider and to always check your blood glucose level before driving. If you’re taking a long trip, plan to pull over and check your blood glucose level every two hours, eat all snacks and meals on schedule, and share the driving with someone else.

Taking such steps greatly increases the likelihood of a safe drive, but unfortunately, even the best prevention can’t guarantee that you won’t develop hypoglycemia. That’s why it’s good to know about some symptoms of hypoglycemia that are typical of (if not unique to) driving. Two typical characteristics of a driver with hypoglycemia are that he develops a sort of one-track mind, in which continuing to drive becomes the sole goal, and that he loses the ability to remember where he is or how to get to his final destination. A driver may, for example, miss the exit to a familiar destination, drive steadily in one direction with no change in driving speed, or drive for many miles beyond his destination. Other peculiar driving behavior reported by family members of people driving with hypoglycemia include stopping at all traffic lights no matter what the color of the light.

Often, passengers are the first to notice that something is awry. However, if you are alone in the car and have the sense that you’re lost or don’t know where you’re going, you should pull over as soon as it’s safe and check your blood glucose level. (If you don’t have a meter with you when you experience symptoms of hypoglycemia, you should go ahead and treat without checking.) You should do the same if you recognize any other possible symptoms of hypoglycemia such as double vision.

Because of the increased responsibility that comes with driving, you should confirm that your blood glucose has returned to a safe level after consuming some carbohydrate before resuming driving. Even if you’re in a hurry, you need to change your priorities, especially before resuming a long trip, to ensure your safety and the safety of others.

Wearing or carrying medical identification specifying that you have diabetes is always a good idea, and it’s especially true while driving. If you pass out at the wheel or are driving erratically because of hypoglycemia, other drivers and the police may assume that you’re drunk. In addition, if your blood glucose level is so low that you do not recognize the authority of the police, you may argue or fight with an officer who pulls you over or approaches you, increasing the likelihood that he’ll think you’re under the influence of alcohol or other drugs.

However, the police are required to look at a person’s wrist, neck, and wallet for medical identification. If you have it, you have a better chance of getting the treatment you need. If you don’t have it, you may be placed in a holding room at a jail and not receive any help.

Because others could mistake hypoglycemia for something else, many parents of teenagers with diabetes require that their teens get in the habit of wearing identification before they are allowed to take driver’s education. Parents are also demanding that teens check their blood glucose level before driving and delay driving until their blood glucose is in a safe range. These same rules should be followed by drivers of any age who are at risk for hypoglycemia. If you frequently experience severe hypoglycemia, however, you may not receive a physician’s clearance for a driver’s license until you have proven that your diabetes is under control.

Hypoglycemia while sleeping

Detecting hypoglycemia while sleeping poses many challenges for people with diabetes. When you are asleep, you cannot tell if your fingers are shaking. In addition, you may not realize that you have double vision or notice weakness or fatigue. But there are some symptoms that may wake you up or partially arouse you, including the following:

• Sweating may alert you or your spouse that you are having hypoglycemia, especially if profuse sweating has made you cold or made your pillow or sheets cold and wet. If you awaken to cold, wet sheets or pajamas, you may be tempted to just change clothes or get a dry sheet and go back to sleep as quickly as possible. But you need to consume some carbohydrate and do a thorough job of treating your low blood sugar to avoid more problems later. Avoid the desire to ignore the problem.

• A fast heartbeat may not be apparent to someone in deep sleep, but it may catch your attention when you roll over. For this symptom to be useful, you have to learn to recognize that a fast heartbeat is a symptom of something very wrong and take action.

• Having a headache in the middle of the night or upon waking is a symptom of hypoglycemia that requires prompt action and more frequent monitoring during the day.

• Nightmares or simply strange dreams can be a symptom of hypoglycemia. Some people describe being “stuck in the same dream.” Others remember having “a long dream,” “an intense dream,” or “daydreaming at night.” What is important is to recognize how your dreams are different during nighttime hypoglycemia and to respond by getting up and checking your blood glucose level if you notice such dreams.

• A person experiencing severe hypoglycemia during sleep would be unable to help himself, but his condition would be evident to others if they were unable to arouse him or if he were having convulsions.

Treatment for mild nighttime hypoglycemia includes eating or drinking some carbohydrate. If it will be many hours before you wake up for breakfast, you should also have a substantial snack containing carbohydrate so that your blood glucose doesn’t go low again during the night. Usually, treatment for severe hypoglycemia during the day is to either call an ambulance or give glucagon. In contrast, for severe nighttime hypoglycemia, many health-care providers recommend doing both: giving glucagon and calling an ambulance, because the person may have been severely low for some time before anyone realized there was a problem. If so, glucagon may not be effective because the liver’s supply of glycogen may be depleted.

After an episode of nighttime hypoglycemia, it’s important to think about how to prevent future episodes. Review your exercise, food intake, and medicine intake from the previous evening or day to look for clues to the cause of your hypoglycemia. If you cannot readily determine the cause or correct the problem on your own, contact your health-care provider for help.

Preventing hypoglycemia

When you were first informed about hypoglycemia by your doctor or diabetes educator, you may not have paid a lot of attention or felt too concerned about it. It is often not until the first mild or moderate hypoglycemia episode that you or your family members learn the value of avoiding low blood glucose.

You can reduce your chances of developing hypoglycemia by learning to make adjustments in your diabetes control regimen to accommodate different activities and circumstances. For example, if you find you tend to develop hypoglycemia after a certain type of exercise, you can learn (with the help of your doctor or diabetes educator) how to adjust your food or medicine on the days you perform that exercise. Keeping a blood glucose monitoring log and regularly reviewing it with your health-care provider can help to determine where problems may be occurring and how to fix them.

Your goal is to find a healthy balance to keep your blood glucose level in target range most of the time. You should not have low blood glucose frequently, but you also should not maintain high blood glucose to avoid hypoglycemia, because having chronically high blood glucose has consequences, too. By learning about the many symptoms of hypoglycemia and paying attention to the symptoms you experience, you have empowered yourself to seek treatment faster. You should not have to give up the things that are important to you such as exercise, playing with your children, or driving just because you could develop hypoglycemia. And with adequate education, planning, and attention, you won’t have to.

Want to learn more about how to handle low blood sugar? Read “Treating Hypoglycemia: No One-Size-Fits-All Solution” and “Understanding Hypoglycemia.”

Originally Published July 25, 2006

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