Introduction

Low blood sugar (hypoglycemia) occurs in people with diabetes when the sugar (glucose) level in the blood drops below what the body needs to function normally.

Key points

• If your blood sugar drops below 70 milligrams per deciliter (mg/dL), you most likely will have symptoms, such as feeling tired, weak, or shaky.
• If your blood sugar drops very low (usually below 20 mg/dL) and you do not get help, you could become confused, drowsy, or even lose consciousness and possibly die. If you are pregnant, your baby could be harmed.
• Low blood sugar can develop if you take too much insulin, do not eat enough food or skip meals, exercise without eating enough, or drink too much alcohol (especially on an empty stomach).
• You can usually treat mild—and sometimes moderate—low blood sugar by eating something that contains sugar.
• You should teach your friends and coworkers what to do if your blood sugar is very low.

 What is a low blood sugar (hypoglycemia) emergency?
 Why do I need to deal with low blood sugar emergencies?
 How to deal with low blood sugar emergencies
 Where to go from here

More information about diabetes can be found in these topics:

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

Return to topic:

What is a low blood sugar (hypoglycemia) emergency?

Low blood sugar (hypoglycemia) means that the level of sugar (glucose) in your blood has dropped below what your body needs to function normally. When your blood sugar level drops below 70 mg/dL, you most likely will have symptoms, such as feeling tired, weak, or shaky. Symptoms of low blood sugar can develop quickly.

• If your blood sugar level drops just slightly below your target range, you may have symptoms of mild low blood sugar. If you eat something that contains sugar, these symptoms may last only a short time. If you have had diabetes for many years, you may not always notice symptoms of mild low blood sugar. This is called hypoglycemia unawareness.
• If your blood sugar level continues to drop (usually below 40 mg/dL), your behavior may change. Symptoms of moderate low blood sugar may start. You may become too weak or confused to eat something to raise your blood sugar level.
• 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.

Sometimes people with diabetes have low blood sugar levels during the night. If your blood sugar level drops during the night, you may wake up in a cold sweat and feel weak or you may sleep through it. Your body may use stored sugar to raise your blood sugar level back toward your target range. If this happens, you most likely will wake up in the morning with a headache and possibly high blood sugar.

What causes low blood sugar?

Low blood sugar (hypoglycemia) can develop rapidly (within 10 to 15 minutes). It can occur if you:

• Take too much insulin.
• Skip or delay a meal or snack.
• Exercise too much without eating enough food.
• Drink too much alcohol, especially on an empty stomach.
• Take certain medicines that lower blood sugar. Some medicines that you can buy without a prescription can affect blood sugar levels. Talk with your doctor about your prescription and nonprescription medicines and whether they may increase your risk of developing very low blood sugar levels.
• Start your menstrual period. The hormonal changes may affect how insulin works.

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. But 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.

Test Your Knowledge

1. Low blood sugar means that the level of sugar in the blood has dropped below what the body needs to function normally (usually below 70 mg/dL).
1. True
   

   The answer is correct

   Low blood sugar means that the level of sugar in the blood has dropped below what the body needs to function normally, usually below 70 mg/dL. When your blood sugar level drops below 70 mg/dL, you most likely will have symptoms, such as feeling tired, weak, or shaky.

   
2. False
   

   The answer is incorrect

   Low blood sugar does mean that the level of sugar in the blood has dropped below what the body needs to function normally, usually below 70 mg/dL. When your blood sugar level drops below 70 mg/dL, you most likely will have symptoms, such as feeling tired, weak, or shaky.

   
2. A very low blood sugar level (below 20 mg/dL) is an emergency that requires immediate care.
1. True
   

   The answer is correct

   A very low blood sugar level (below 20 mg/dL) is an emergency. You need care immediately. If untreated, a very low blood sugar level can lead to coma and death.

   
2. False
   

   The answer is incorrect

   A very low blood sugar level (below 20 mg/dL) is an emergency. You need care immediately. If untreated, a very low blood sugar level can lead to coma and death.

   

Continue to Why do I need to deal with low blood sugar emergencies?
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Why do I need to deal with low blood sugar emergencies?

If untreated, very low blood sugar can lead to serious illness and death.

When your blood sugar level falls below 70 mg/dL (55 mg/dL if you are pregnant), your body reacts like it does when you feel very afraid, angry, or anxious. You may feel weak, shaky, and/or sweaty. But if you eat something that contains sugar, your blood sugar level most likely will rise. An emergency likely will not develop, and you will not have any long-lasting effects from having low blood sugar.

If your blood sugar continues to drop (below 40 mg/dL), your brain may receive too little sugar to work properly and your judgment and muscle coordination will be affected. These are symptoms of moderate low blood sugar. You may not realize your blood sugar is too low, and you may not be aware that you need to eat food with sugar to raise the level. Someone else may have to help you eat or drink something to raise your blood sugar level. If you do not get help, you could get in an accident if you are driving a car or operating other machinery. If you are pregnant, low blood sugar can harm your baby.

If your blood sugar continues to drop (below 20 mg/dL), you can lose consciousness. If you do not receive prompt emergency care, you may have a seizure, heart attack, or stroke and possibly die. These are symptoms of severe low blood sugar. If you are pregnant and taking insulin, very low blood sugar levels are dangerous for your baby.

A low blood sugar level may soon recur, even though it has been treated. Check your blood sugar often after a low level has been treated to make sure your blood sugar returns to normal.

Test Your Knowledge

1. If my blood sugar level drops very low (below 20 mg/dL):
1. I can fall into a coma and possibly die.
   

   The answer is correct

   If your blood sugar level drops to 20 mg/dL or lower, you can fall into a coma and possibly die. Blood sugar levels in people who take insulin can drop very low rapidly (in 10 to 15 minutes).

   
2. I will act like I am okay.
   

   The answer is incorrect

   If your blood sugar level drops to 20 mg/dL or lower, you will not act like you are okay. The correct answer is a. If your blood sugar level drops to 20 mg/dL or lower, you can fall into a coma and possibly die. Blood sugar levels in people who take insulin can drop very low rapidly (in 10 to 15 minutes).

   
3. I will be able to eat or drink something to raise it.
   

   The answer is incorrect

   If your blood sugar level drops to 20 mg/dL or lower, you will not be able to eat or drink something to raise it. Someone else will need to help you eat or drink something or you may need emergency medical help. The correct answer is a. If your blood sugar level drops to 20 mg/dL or lower, you can fall into a coma and possibly die. Blood sugar levels in people who take insulin can drop very low rapidly (in 10 to 15 minutes).

   

Continue to How to deal with low blood sugar emergencies
Return to Diabetes: Dealing with low blood sugar from insulin

How to deal with low blood sugar emergencies

Here are some ways you can manage low blood sugar.

Be prepared

Always be prepared for the possibility of having a low blood sugar level.

• Keep some quick-sugar foods with you at all times. If you are at home, you will probably already have something close at hand that contains sugar, such as table sugar or fruit juice. Carry some hard candy or glucose tablets with you when you are away from home. The list of quick-sugar foods gives some examples of foods and how much you need to eat to raise your blood sugar. The foods on this list will help raise your blood sugar by about 30 mg/dL in 15 minutes.
• Know the symptoms of low blood sugar. Post the symptoms of low blood sugar where you will see it often and carry a copy in your wallet or purse. Add any symptoms you have noticed that may not be on the list. Be sure that your partner (and others) knows your early symptoms, including the signs of low blood sugar at night.
• Wear medical identification. Always wear medical identification, such as a medical alert bracelet, to let people know that you have diabetes. In case your blood sugar drops very low and you need help, people will know that you have diabetes and will get help for you if necessary.
• Keep glucagon on hand. If you become unconscious when your blood sugar is very low, someone may need to give you a shot of glucagon to raise your blood sugar. Be sure someone knows how to give you the shot. Have the person practice by giving you your insulin shot once or twice a month. This will help the person be confident if he or she has to give you a shot of glucagon in an emergency. Keep the instructions for how to give glucagon with the medicine. Also, check the expiration date on your glucagon. Most kits need to be replaced every 6 months.
• Teach others (at work and at home) how to check your blood sugar in case you cannot check it yourself. Have instructions for how to use your blood sugar (glucose) meter to check your blood sugar with the meter so the person can review the instructions.
• Teach other people (at work and at home) what to do in case your blood sugar becomes very low. Post the emergency care for low blood sugar in a convenient place at home and at work. Go over with others the steps they need to take when your blood sugar is very low.

Treat low blood sugar early

Treat low blood sugar levels as soon as you (or someone else) notice the symptoms.

• Check your blood sugar often. If you have had diabetes for many years, you may not have symptoms until your blood sugar is very low. Checking your blood sugar regularly and also whenever you think it may be low will take the guesswork out of treating low blood sugar levels.
• Follow the steps for dealing with low blood sugar when you first develop your symptoms of low blood sugar or when your blood sugar level is below 70 mg/dL. Encourage others to tell you if they notice you are developing signs of low blood sugar.
• Keep a record. Write down your symptoms and how you treated your low blood sugar. Use the low blood sugar level record(What is a PDF document?) .
• Notify your doctor. Let her or him know if you are having low blood sugar problems. Your insulin dosage may need to be adjusted.

Test Your Knowledge

1. To be prepared for a low blood sugar emergency, I need to carry:
1. My insulin.
   

   The answer is incorrect

   To be prepared for a low blood sugar emergency, you do not need to carry your insulin. A dose of insulin will make your blood sugar drop lower. The correct answer is b. To be prepared for a low blood sugar emergency, always have some quick-sugar foods with you.

   
2. Some quick-sugar foods.
   

   The answer is correct

   To be prepared for a low blood sugar emergency, you need to carry some quick-sugar foods with you at all times.

   
2. To treat low blood sugar before it becomes an emergency, I need to:
1. Take an extra dose of insulin.
   

   The answer is incorrect

   To treat low blood sugar before it becomes an emergency, you do not need to take an extra dose of insulin. An extra dose of insulin will make your blood sugar drop lower. The correct answer is c. Eat some food that contains sugar to raise your blood sugar level.

   
2. Go to sleep and rest.
   

   The answer is incorrect

   To treat low blood sugar before it becomes an emergency, you should not go to sleep and rest. Your blood sugar level may continue to drop, leading to an emergency. The correct answer is c. Eat some food that contains sugar to raise your blood sugar.

   
3. Eat some food that contains sugar.
   

   The answer is correct

   To treat low blood sugar before it becomes an emergency, you need to eat some food that contains sugar. Food that contains sugar will raise your blood sugar.

   

Continue to Where to go from here
Return to Diabetes: Dealing with low blood sugar from insulin

Where to go from here

Now that you have read this information, you are ready to start dealing with low blood sugar levels effectively.

Talk with your doctor or certified diabetes educator

If you have questions about this information, take it with you when you visit your doctor or diabetes educator. You may want to mark areas or make notes in the margins of the pages where you have questions.

If you don't already have glucagon at home, ask your doctor for a prescription. Make sure someone knows how to give you a glucagon shot if an emergency develops. You may want to have two glucagon kits so that if one gets used, you have a backup.

If you would like more information on dealing with low blood sugar levels, the following resources are available:

Organization

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