Health Library Diabetes-Related High and Low Blood Sugar LevelsFrom Healthwise

When you have diabetes, you may have high blood sugar levels (hyperglycemia) or low blood sugar levels (hypoglycemia) from time to time. A cold, the flu, or other sudden illness can cause high blood sugar levels. You will learn to recognize the symptoms and distinguish between high and low blood sugar levels. Insulin and some types of diabetes medicines can cause low blood sugar levels.

Learn how to recognize and manage high and low blood sugar levels to help you avoid levels that can lead to medical emergencies, such as diabetic ketoacidosis or dehydration from high blood sugar levels or loss of consciousness from severe low blood sugar levels. Most high or low blood sugar problems can be managed at home by following your health professional's instructions.

Following your health professional's instructions on the use of insulin or diabetes medicines, diet, and exercise will help you avoid blood sugar problems. Home blood sugar testing will help you determine whether your blood sugar is within a safe range. If you have had very low blood sugar, you may be tempted to let your sugar level run high so you do not have another low blood sugar problem. However, it is most important that you keep your blood sugar in a safe range. You can do this by following your treatment plan and checking your blood sugar regularly.

Children with diabetes need their parents' help to keep their blood sugar levels in a safe range and to exercise safely. It is important for children to learn the symptoms of both high and low blood sugar so they can tell others when they need help. There are many support groups and diabetes education centers to help parents and children understand about blood sugar, exercise, diet, and medicines.

Teens especially may have a hard time keeping their blood sugar levels in control because their bodies are growing and developing. Also, they want to be with their friends and eat foods that may affect their blood sugar. Having diabetes during the teenage years is not easy. However, your teen is at an excellent age to understand the disease and its treatment and to take over some of the responsibilities of his or her care.

If your blood sugar level reads too high or too low but you are feeling well, you may want to recheck your sugar level or recalibrate your blood glucose meter. The problem may be with either your blood sample or the machine.

High blood sugar (hyperglycemia)

High blood sugar occurs when the sugar (glucose) level in your blood rises above normal. Eating too many calories, missing medicines (insulin or pills), or having an infection or illness, injury, surgery, or emotional stress can cause your blood sugar to rise.

High blood sugar usually develops slowly over a period of hours to days. However, missing a dose of insulin can cause a rapid rise in blood sugar levels. Blood sugar levels just above the safe range may make you feel tired and thirsty. If your blood sugar level stays higher than normal for weeks, your body will adjust to that level, and you may not have as many symptoms of high blood sugar.

Unless you don't monitor your blood sugar regularly or you don't notice the symptoms of high blood sugar, you usually will have time to treat high blood sugar so that you can prevent high blood sugar emergencies. Three things can help you prevent high blood sugar problems:

• Test your blood sugar often, especially if you are sick or are not following your normal routine. You can see when your blood sugar is above the safe range, even if you don't have symptoms of high blood sugar such as increased thirst, increased urination, and fatigue. Then you can treat it early, preventing an emergency.
• Notify your health professional if you have frequent high blood sugar levels or if your blood sugar level is consistently staying above the safe range. Your medicine may need to be adjusted or changed.
• Drink extra water or non-caffeinated, non-sugared drinks so you will not be dehydrated. If your blood sugar continues to rise, your kidneys will increase the amount of urine produced, and you can become dehydrated.

Complications of high blood sugar can cause serious problems, including coma and death. Over time, high blood sugar can damage your eyes, heart, kidneys, blood vessels, and nerves.

Low blood sugar (hypoglycemia)

Low blood sugar occurs when the sugar (glucose) level in your blood drops below what your body needs. Not eating enough food or skipping meals, take too much medicine (insulin or pills), exercising more than usual, or taking certain medicines that lower blood sugar can cause your blood sugar to drop rapidly.

People who lose weight or develop kidney problems may not need as much insulin or other medicines as they did before they lost the weight or developed kidney problems. Their blood sugar may drop too low. It is important to check your blood sugar often when your body goes through changes.

When your blood sugar level drops below 70 milligrams per deciliter (mg/dL), you will usually have symptoms of low blood sugar. This can develop quickly, in 10 to 15 minutes.

• If your blood sugar level drops just slightly below a safe range (mild low blood sugar), you may feel tired, anxious, weak, shaky, or sweaty, and you may have a rapid heart rate. If you eat something that contains sugar, these symptoms may last only a short time. If you have diabetes, you may not always notice symptoms of mild low blood sugar. This is called hypoglycemia unawareness. If your blood sugar is well-controlled and does not change much during the day, you may have an increased risk for hypoglycemic unawareness.
• If your blood sugar level continues to drop (usually below 40 mg/dL), your behavior may change, and you may feel more irritable. You may become too weak or confused to eat something with sugar to raise your blood sugar level. Anytime your blood sugar drops below 50 mg/dL, you should act whether you have symptoms or not.
• If your blood sugar level drops very low (usually below 20 mg/dL), you may lose consciousness or have a seizure. If you have symptoms of severe low blood sugar, you need medical care immediately.

You may have symptoms of low blood sugar if your blood sugar drops from a high level to a lower level. For example, if your blood sugar level has been higher than 300 mg/dL for a week or so and the level drops suddenly to 100 mg/dL, you may have symptoms of low blood sugar even though your blood sugar is in the normal range. However, if you have had diabetes for many years, you may not have symptoms of low blood sugar until your blood sugar level is very low.

If your health professional thinks you have low blood sugar levels but you are not having symptoms, he or she may ask you to check your blood sugar more often. Your health professional may ask you to check your blood sugar in the middle of the night or to use a 3-day continuous glucose monitor test.

Review the Emergencies and Check Your Symptoms sections to determine if and when you need to see a health professional.

Health tools help you make wise health decisions or take action to improve your health.

	Actionsets are designed to help people take an active role in managing a health condition.
	Diabetes in children: Dealing with low blood sugar
	Diabetes in children: Preventing high blood sugar
	Diabetes in children: Preventing low blood sugar
	Diabetes: Dealing with low blood sugar from insulin
	Diabetes: Dealing with low blood sugar from medicines
	Diabetes: Preventing high blood sugar emergencies
	Gestational diabetes: Dealing with low blood sugar

Does the person with diabetes have any of the following symptoms:

• Unconsciousness
• A seizure. See protecting a victim from harm during a seizure.
• Severe dehydration is present:
  • In a child.
  • In an adult or older child.
• A person is losing consciousness or becoming sleepy or lethargic and is not able to swallow water without choking or coughing, preventing him or her from following the appropriate guidelines for low blood sugar levels.

Note:

If a person becoming sleepy or lethargic but is able to swallow water without choking or coughing, check his or her blood sugar. If the person has a blood sugar level less than 60 mg/dL, follow the appropriate guidelines for emergency care for low blood sugar. A child who takes insulin A child who takes only oral diabetic medicine An adult or adolescent who takes insulin An adult or adolescent who does not take insulin injections A woman who has gestational diabetes

If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.

Review health risks that may increase the seriousness of your symptoms.

	Yes	Is your blood sugar level high?
When to See a Doctor See significance of high blood sugar levels if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Note: If your health professional has given you specific instructions to follow for a high blood sugar level, be sure to follow those instructions. If you have a high blood sugar level, take steps to lower your blood sugar level by following these guidelines: Steps for dealing with high blood sugar in a child Steps for dealing with high blood sugar in an adult Call your health professional immediately if you answer "Yes" to any of the following questions. Yes Do you have symptoms of ketoacidosis? Symptoms of ketoacidosis include: Flushed, hot, dry skin. A strong, fruity breath odor (similar to nail polish remover or acetone). Restlessness, drowsiness or difficulty waking up. Young children may lack interest in their normal activities. Rapid, deep breathing. Loss of appetite, abdominal pain, and vomiting. Confusion. Yes Do you have symptoms of moderate dehydration? Symptoms of dehydration in a child Symptoms of dehydration in an adult Yes Do you have nausea or vomiting and are unable to keep fluids down? Yes Do you have a moderate to large amount of ketones in your urine? Yes Do you have signs of infection? These signs may include: Increased pain, swelling, redness, or warmth around the affected area. Red streaks extending from the affected area. Drainage of pus from the area. Yes Do you have a fever or think you have a fever but you are unable to measure your temperature? Call your health professional today if you answer "Yes" to any of the following questions. Yes Do you have symptoms of mild to moderate high blood sugar (symptoms of high blood sugar), and your symptoms are increasing after taking steps to lower your blood sugar level? Yes Do you have symptoms of mild dehydration, and your symptoms are increasing after taking steps to lower your blood sugar level? Symptoms of dehydration in a child Symptoms of dehydration in an adult Yes Is your blood sugar level over 400 mg/dL after you test your blood twice and your usual plan for lowering your blood sugar is not working, but you do not have symptoms of high blood sugar? Yes Is your blood sugar level high and continues to rise after you have taken steps to lower your blood sugar level, but you do not have symptoms of high blood sugar? Yes Is your blood sugar level over 200 mg/dL and you are not sure what you should do? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question. Yes Are you concerned that your episodes of high blood sugar levels are occurring more frequently? If you have answered "No" to the above questions, continue to answer the questions to evaluate your symptoms.
	Yes	Is your blood sugar level low?
When to See a Doctor See significance of low blood sugar levels if you need information to help you answer the questions below. Review health risks that may increase the seriousness of your symptoms. Note: If your health professional has given you specific instructions to follow for a low blood sugar level, be sure to follow those instructions. If you have a low blood sugar level, follow these guidelines to get your blood sugar level higher. A child who takes insulin A child who takes only oral diabetes medicine An adult or adolescent who takes insulin An adult or adolescent who does not take insulin injections A woman who has gestational diabetes Call your health professional immediately if you answer "Yes" to the following question. Yes After a half-hour of initiating steps to raise your blood sugar level, is your level under 70 mg/dL? You need an appointment within the next 1 to 2 weeks if you answer "Yes" to any of the following questions. Yes Are you concerned that your episodes of low blood sugar levels are occurring more frequently? Yes Have you had low blood sugar levels without any symptoms? If you have answered "No" to the above questions, continue to answer the questions to evaluate your symptoms.

Other Symptoms to Watch For

The information in this topic is specific to diabetes-related high and low blood sugar levels. The following symptoms may affect your blood sugar levels:

• Nausea and vomiting: Go to the topic Nausea and Vomiting, Age 4 and Older.
• Dehydration: Go to the topic Dehydration.
• Diarrhea: Go to the topic Diarrhea, Age 12 and Older.

If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.

When you have diabetes, whether it is type 1 diabetes, type 2 diabetes, or gestational diabetes, one of the most important skills you will learn is how to manage your blood sugar level. Following your health professional's instructions on the use of insulin or diabetes medicines, diet, and exercise will help you avoid blood sugar problems. You will learn to recognize the symptoms and distinguish between high and low blood sugar levels. It may be difficult for a parent of a young child to distinguish the difference between high and low blood sugar symptoms in a child.

Learn the symptoms of high and low blood sugar levels.

• Symptoms of high blood sugar levels
• Symptoms of low blood sugar levels

Once you have learned to recognize high or low blood sugar levels, you can take the appropriate steps to bring your blood sugar level back to target blood sugar levels.

People who keep their blood sugar levels under control with diet, exercise, or oral diabetes medicines are less likely to have problems with high or low blood sugar levels.

Learn how to deal with high blood sugar levels. Be sure to know how fast your insulin medicine will work to bring your blood sugar down. Some insulins work very fast while regular insulin takes a little longer to bring the sugar level down. Knowing how fast your insulin works will keep you from using too much too quickly.

• Steps for dealing with high blood sugar in a child
• Steps for dealing with high blood sugar in an adult

Learn how to deal with low blood sugar levels. Because you have diabetes and can have low blood sugar levels, you need to keep some type of food with you at all times that can quickly raise your blood sugar level. These should be quick-sugar foods (about 15 to 20 grams of carbohydrate) that puts glucose into your bloodstream in about 5 minutes. Any quick-sugar food on this list will raise your blood sugar about 30 milligrams per deciliter (mg/dL) in about 15 to 20 minutes. Be sure to check your blood sugar level again 15 minutes after eating a quick-sugar (carbohydrate) food to make sure your level is getting back to a safe range. When your blood sugar gets to 70 mg/dL or higher, you can eat your normal meals and snacks.

It is important to know that sugar foods like a candy bar or ice cream do not help raise low blood sugar levels quickly because these foods also have fat and protein. So the body cannot use the sugar (carbohydrate) in these foods quickly to raise the blood sugar level.

Diabetes in children: Preventing low blood sugar

Diabetes in children: Dealing with low blood sugar

Diabetes: Dealing with low blood sugar from insulin

Diabetes: Dealing with low blood sugar from medicines

Gestational diabetes: Dealing with low blood sugar

Since low blood sugar levels can quickly become a medical emergency, it is important that you wear a bracelet or necklace or carry a card that says:

• I have diabetes.
• Emergency treatment is needed for a severe low blood sugar level.

If you have severe symptoms of low blood sugar, someone else may need to give you a shot of glucagon. If this occurs, be sure to call your health professional immediately to let him or her know this has happened.

Symptoms to Watch For During Home Treatment

Use the Check Your Symptoms section to evaluate your symptoms if any of the following occur during home treatment.

• Symptoms of high blood sugar develop.
• Symptoms of low blood sugar develop.
• Symptoms become more severe or frequent.

Although high blood sugar (hyperglycemia) and low blood sugar (hypoglycemia) have very different symptoms and treatments, they are both caused by blood sugar and insulin imbalances. The steps you take to control your blood sugar level will help prevent both high and low blood sugar levels.

Be sure to have identification with you at all times that says you have diabetes. This will help other people take steps to care for you if you are not able tell them about your medical condition.

You can take steps to prevent high and low blood sugar emergencies.

• Follow your treatment plan.
• Monitor your blood sugar levels regularly to detect early changes before an emergency develops. Treat your symptoms of high or low blood sugar quickly to prevent more problems.
• Control your stress.
• Limit how much alcohol you drink.

Monitoring and controlling blood sugar levels

Use home blood sugar tests to determine whether your blood sugar is in the safe range. Work with your health professional to set your individual treatment goals. If you can consistently maintain this level of control, you will have very few blood sugar level emergencies.

Control stress

No matter how skilled you are at monitoring and controlling your blood sugar levels, you are still at risk for high or low blood sugar levels that are brought on by stressful situations. Stress can affect your body's blood sugar levels in two ways:

• It changes the way your body uses insulin, which is mostly a problem for people with type 2 diabetes.
• It can cause you to change the way you take care of yourself, a problem for all people with diabetes.

Stress can be both mental and physical. Some examples of stress include an illness, a bad day at work, and a tough problem at home. When you are under stress, your blood sugar levels change. For more information, see the topic Stress Management.

Diabetes: Preventing high blood sugar emergencies

Diabetes in children: Preventing high blood sugar

Blood sugar levels and exercise

You can keep your blood sugar levels under control when you exercise, so that you do not become too hungry or make your blood sugar level drop. There are two ways to keep your blood sugar levels under control:

1. At the meal before your planned exercise, you can take less insulin, OR
2. Before you exercise, eat some carbohydrate.

Keep a quick-sugar food with you during exercise in case your blood sugar level drops low.

Vaccinations

Your health professional may recommend that you get vaccinations, such as a flu (What is a PDF document?) shot or pneumonia (What is a PDF document?) shot, to prevent you from those illnesses.

Other places to get help

The American Diabetes Association has a lot of information on diabetes and can link you to support groups. For more information, call 1-800-DIABETES (1-800-342-2383) or see the organization's Web site: http://www.diabetes.org/home.

To prepare for your appointment, see the topic Making the Most of Your Appointment.

You can help your health professional treat your condition by being prepared to answer the following questions:

• What steps did you take to correct your high or low blood sugar level? Did they help?
• Have you had signs of another illness?
• Have you made any recent changes in your diet, exercise, or medicines?
• What other prescription and nonprescription medicines do you take?
• Have you recently had increased emotional or physical stress?
• Have you noticed situations that trigger or may cause your high or low blood sugar problem?
• Have you noticed any patterns, such as time of day, when your high or low blood sugar problem occurs?
• Have you used a high blood sugar card? If so, be sure to bring it when you see your health professional. See an example of a high blood sugar card (What is a PDF document?) .
• Do you have other health risks?

Be sure to take your daily blood sugar (glucose) monitoring logbook to your appointment. If you have specific records of your blood sugar problems, be sure to take those records.

• High blood sugar level record for an adult (What is a PDF document?)
• High blood sugar level record for a child (What is a PDF document?)
• Low blood sugar level record for an adult (What is a PDF document?)
• Low blood sugar level record for a child (What is a PDF document?)

Organization

• Gestational Diabetes
• Type 1 Diabetes
• Type 1 Diabetes: Children Living With the Disease
• Type 1 Diabetes: Living With Complications
• Type 1 Diabetes: Living With the Disease
• Type 1 Diabetes: Recently Diagnosed
• Type 2 Diabetes
• Type 2 Diabetes in Children
• Type 2 Diabetes: Living With Complications
• Type 2 Diabetes: Living With the Disease
• Type 2 Diabetes: Recently Diagnosed

Author:	Jan Nissl, RN, BS	Last Updated: November 18, 2006
Medical Review:	Martin Gabica, MD - Family Medicine Caroline S. Rhoads, MD - Internal Medicine Matthew I. Kim, MD - Endocrinology & Metabolism
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