(Low Blood Glucose)

Causes, Symptoms,
Treatment & Prevention


Islets of Hope Publication HG-1-2006
You may use and distribute this information freely, but please reference www.IsletsofHope.com


(LOW Blood Glucose)

Onset:  Rapid; sudden, may not be preventable.

Causes Related to Diabetes: Missing snacks or meals, eating too little food, taking too much insulin, too much activity, side effects of medications taken, or a combination of these things.

ALERT:  All lows are potentially dangerous and can lead to seizure, convulsion, unconsciousness, and death if not treated.  If you are unable to test someone's blood glucose, always assume the person is low and treat for low blood glucose.  Call 911 and test blood glucose as soon as possible.


Important Medical Disclaimer

All material found in this publication is intended to provide you with general information and should in no way be used as a substitute for professional medical care or advice.


Hypoglycemia (Low Blood Glucose)
Causes, Symptoms,
Treatment & Prevention

Islets of Hope Publication HG-1-2006



  3        About Hypoglycemia   
  3        Happy:  An Immediate Danger  
  4        Normal & Target Blood Glucose Levels  

  5        Symptoms of Hypoglycemia

  6        Common Causes of Low Blood Glucose  
  6        Side Effect of Certain Medications   
  7        Insulin Pumps & Hypoglycemia    
  7        Bathing, Saunas, Hot Weather & Exercise Can Cause Hypoglycemia   

  8        Treatment     
  8        When to Inject Glucagon     
  9        Do Not Turn off Insulins Pumps to Treat Hypoglycemia   

 10       Preventing Hypoglycemia   
 10       Preventing Hypoglycemia During the Day

 10       Preventing Hypoglycemia During the Night

 12       Summary of Symptoms of Hypoglycemia

 13       Emergency Care Instructions for Person with Hypoglycemia



About Hypoglycemia

Hypoglycemia, also called low blood sugar, occurs when your blood glucose (blood sugar) level drops too low to provide enough energy for your body's activities. In adults or children older than 10 years, hypoglycemia is uncommon except as a side effect of diabetes treatment, but it can result from other medications or diseases, hormone or enzyme deficiencies, or tumors.

Glucose, a form of sugar, is an important fuel for your body. Carbohydrates are the main dietary sources of glucose. Rice, potatoes, bread, tortillas, cereal, milk, fruit, and sweets are all carbohydrate-rich foods.

After a meal, glucose molecules are absorbed into your bloodstream and carried to the cells, where they are used for energy. Insulin, a hormone produced by your pancreas, helps glucose enter cells. If you take in more glucose than your body needs at the time, your body stores the extra glucose in your liver and muscles in a form called glycogen. Your body can use the stored glucose whenever it is needed for energy between meals. Extra glucose can also be converted to fat and stored in fat cells.

When blood glucose begins to fall, glucagon, another hormone produced by the pancreas, signals the liver to break down glycogen and release glucose, causing blood glucose levels to rise toward a normal level. If you have diabetes, this glucagon response to hypoglycemia may be impaired, making it harder for your glucose levels to return to the normal range.

The key to avoiding complications with diabetes is to manage blood glucose levels judiciously.  Long-term complications of diabetes are very serious, diminish quality of life, and can take years off your life span.  But long-term problems don't develop magically on their own, they happen slowly over time when daily care is mismanaged.  This is one of the reasons why so many health care professionals are advocates of tight diabetes control.

Hypoglycemia:  An Immediate Danger

Low blood glucose levels present immediate danger -- they must be treated (but not over treated) to avoid insulin shock or death.  Frequent lows indicate brittle diabetes, that is, too much insulin is being administered or, that is being improperly timed, to handle snacks, meals and activity levels.  It is important that you report severe or frequent lows to your physician so that he/she can help you make any necessary adjustments in your care.  



Normal and Target Blood Glucose Ranges (mg/dL)

Normal blood glucose levels in people who do not have diabetes:
Upon waking (fasting) 70 to 110

After meals

70 to 140
Target blood glucose levels in people who have diabetes:
Before meals 90 to 130
1 to 2 hours after the start of a meal less than 180
Hypoglycemia (low blood glucose) 70 or below

Important Note:  Your doctor may provide you with different target ranges so be sure to know he/she recommends for your blood glucose levels.  

Glucose levels are measured in either:

  • Milligrams per deciliter (mg/dL), in the United States
  • Millimoles per liter (mmol/L) (for those using metric system)


  •  72 mg/dL = 4 mmol/L
  •  90 mg/dL = 5 mmol/L
  • 108 mg/dL = 6 mmol/L
  • 126 mg/dL = 7 mmol/L

Glucose levels vary before and after meals, at various times of day, as well as throughout the night in persons with diabetes as well as in non-diabetics.  It is therefore, important that you understand what target and ranges your doctor sets for you.  If you have trouble meeting your target blood glucose levels you may need to make changes in your diabetes care plan. Call your doctor to learn what adjustments are appropriate for your individual needs.

Morning fasting glucose levels 125 mg/dL or higher could indicate diabetes.



Symptoms of Hypoglycemia
(Low Blood Glucose)

It is important to remember that people can react differently to low blood glucose levels. Generally, symptoms of hypoglycemia include:

Mild Hypoglycemia

  • Increased or sudden hunger
  • Feeling shaky, dizzy or nervous
  • Pounding heartbeat
  • Drowsiness, feeling tired
  • Sweating (cold and clammy)
  • Numbness or tingling around the mouth
  • Headache or stomach ache

Moderate Hypoglycemia
Any of the above mild symptoms, plus:

  • Personality change
  • Irritability
  • Confusion and/or difficulty concentrating
  • Slurred or slow speech
  • Poor coordination

Severe Hypoglycemia    * Give glucagon & CALL 911 ASAP! *
Any of the above mild or moderate symptoms, plus:

  • Loss of consciousness
  • Seizures and/or convulsions
  • Death

Hypoglycemia can also happen while you are sleeping. You might:

  • Cry out or have nightmares
  • Find that your pajamas or sheets are damp from perspiration
  • Feel tired, irritable, or confused when you wake up
  • Wake up with high blood glucose or a headache.  



Common Causes of Hypoglycemia

Causes Related to Diabetes: Missing snacks or meals, eating too little food, taking too much insulin, too much activity, side effects of medications taken, or a combination of these things.

"Stacking" or "piggybacking" insulin is a common cause of hypoglycemia especially in newly diagnosed patients or young children who are unstable or more sensitive to insulin at certain times of the day than at others.  Piggybacking or stacking, simply means giving insulin for correction or food before the previous insulin (on board insulin) is used up resulting in too much insulin in the body.

Another cause for hypoglycemia, especially in young children is excitement.  Studies indicate that children experience more frequent episodes of hypoglycemia around holidays and birthdays than the do at other time.

Another factor that can contribute to hypoglycemia in newly diagnosed patients is when they are "honeymooning" (transient diabetes).  This simply means that the pancreas has not completely shut down yet and from time-to-time will produce some insulin.  

Causes Unrelated to Diabetes may include morning fasting hypoglycemia (an indication that there may be an underlying medical problems, and reactive hypoglycemia.

Side Effect of Certain Medications

Hypoglycemia can occur in people with diabetes who take certain medications to keep their blood glucose levels in control. Usually hypoglycemia is mild and can easily be treated by eating or drinking something with sugar. But left untreated, hypoglycemia can lead to loss of consciousness.

In people taking certain blood-glucose lowering medications, or insulin-sensitizing drugs, blood glucose can fall too low for a number of reasons:

  • Meals or snacks that are too small, delayed, or skipped, especially when on insulin or glucphage.

  • Some diabetes medications, including sulfonylureas and meglitinides (Alpha-glucosidase inhibitors, biguanides, and thiazolidinediones alone should not cause hypoglycemia but can when used with other diabetes medicines.)


Insulin Pumps

If you are on an insulin pump, try to avoid changing out your canula site just before bed time.  New sites can often be more sensitive to insulin, or, if you hit scar tissues, may be less sensitive.  You should always check your blood glucose 1-2 hours after changing your site.  

Bathing, Saunas, Hot Weather & Exercise Can Cause Hypoglycemia

Other causes of hypoglycemia can be attributed to taking baths or using hot tubs and saunas too soon after injecting insulin.  The warmth of the water will increase your insulin sensitivity and result in low blood glucose levels.  It is important to time your shots so that bathing will not alter your sensitivity just before you go to bed.  Trying waiting 1-2 hours after giving insulin before getting into the tub.

Hot weather and exercise also increase insulin sensitivity and circulation; both can contributed to a rapid drop in blood glucose levels.  On warm days, and during exercise be sure to stay well hydrated (drink lots of cool water) to keep your body temperature from rising.

Any activity that raises body temperature can also increase insulin sensitivity and cause a hypoglycemic reaction.

Treatment of Hypoglycemia

If you think your blood glucose is too low, use a blood glucose meter to check your level.  Always treat for hypoglycemia whenever you blood glucose is 70 mg/dL or below.  (You doctor may want you to treat, especially for children, at a slightly higher range.  Be sure to follow the advice of your health care provider).

Immediately take 15 grams of a fast-acting sugar such as:

  • 3-4 glucose tablets (12-16 carbs)
  • 1/2 cup (4 ounces) of any fruit juice (12-15 carbs)
  • 1/2 cup (4 ounces) of a regular (not diet) soft drink (15 carbs)
  • 10 ounces of milk (skim or low-fat milk is better than fatted milk) (15 carbs)
  • 5 or 6 pieces of hard candy (10-15 carbs)
  • 2 teaspoons of sugar or honey

It takes 15 minutes for the food or sugar tablets to raise your blood sugar.  After 15 minutes, check your blood glucose again to make sure that it is no longer too low. If it is still too low, have another serving.  Repeat these steps until your blood glucose is at least 90 (or, whatever your doctor advises). Then, if it will be an hour or more before your next meal, have a snack.

When to Inject Glucagon

Severe hypoglycemia can cause you to lose consciousness, to have seizures, or be disoriented and unable to swallow. In these extreme cases when cannot ingest a fast sugar, glucagon should be injected to quickly raise your blood glucose level.  If you take insulin ask your doctor for a prescription for at least two glucagon kits -- one to keep at home and one to keep with you at all times.  If you have a child in school, you should also have a glucagon kit at school.  Show your family, friends, and co-workers how to give you a glucagon injection in an emergency.  You should also carry medical instructions on how to administer glucagon, a treatment guide for hypoglycemia, as well as medical emergency contact information for anyone who might find you unconscious.

If a person with diabetes is unable to swallow, having seizures, or is unconscious:

  • Immediately give an injection of glucagon
  • Roll the person onto their side (to avoid choking should they vomit)
  • Call 911 last. 

Try not to leave the person alone while they are unconscious. 


After an injection of glucagon it may take 15-20 minutes for the person to wake up.  If by then, paramedics have not arrived and the person is still unconscious give a second injection of glucagon.  When the person is awake give them a balanced snack or meal.

Note:  Fast-acting sugars include glucose tablets, a 10 oz. glass of skim milk (not fatted milk which will not cause a rapid enough rise in blood sugar), or a 4 oz. glass of juice, gumdrops or other candy that is pure sugar and contains no fat.  (Food and candy that contains fat will slow the rise of blood sugar and should not be used for fast-acting sugars.)

If you have diabetes, you should ensure that a member of your family or a friend is properly trained to give you a glucagon injection in the event that you should need it.  You should also carry a medical card that asks anyone finding you unconscious to immediately call 911.  
Do Not Turn off Insulin Pumps to Treat Hypoglycemia

Turning off your insulin pump for more than an hour (only occasionally) is never a good idea.  If your blood glucose levels are low, eat to bring glucose levels back up again.  

If you have hypoglycemia during the night change, or reduce your basals and have a fast sugar or snack if necessary, but don't completely turn off your basal rates on the pump. Turning off your pump for more than an hour (only do this occasionally and as necessary) stops basal insulin from being administered.  This diminishes the amount circulating insulin in your body and can set the stage for quick onset of diabetic ketoacidosis (DKA).  

Children may need to be hospitalized if they are too sick to eat requiring an intravenous glucose solution just so that insulin can continue to be administered.  When there is no circulating insulin in the body (either from the pancreas, shots, or an insulin pump) a person is more likely to experience DKA sooner, and at a lower glucose level, than are persons who have some insulin in their body.

If you wish to go "unteathered" (unhook your pump) ask your doctor how to inject Lantus or other long-acting insulin to replace the basal rate function of the pump.  You can go off and on the pump (reverting to shots) but you cannot go off insulin.  Only your doctor should advise you how to switch back and forth between shots and the pump.

Preventing Hypoglycemia

Preventing Hypoglycemia During the Day

Your diabetes treatment plan is designed to match your medication dosage and schedule to your usual meals and activities. If you take insulin but then skip a meal, the insulin will still lower your blood glucose, but it will not find the food it is designed to break down. This will result in hypoglycemia.

  • Eat and take your medications on time.
  • Make sure you eat enough food for the medication you are taking.
  • Do not drink alcohol without eating food.
  • Be prepared and carry some form of carbohydrates with you in case there is a meal delay.
  • Be aware of the time of day - if you are taking insulin, your blood sugar will be the lowest before a meal and you may be more sensitive to insulin or carbohydrates at various times of the day.
  • Plan your exercise. Eat more to cover unplanned exercise which may lower your blood sugar too much.  Exercise can also cause a rapid drop in blood sugar hours later, so monitor your sugars frequently post heavy exercise.
  • Record and report all unexplained hypoglycemia episodes to your doctor.  


Preventing Hypoglycemia During the Night

Check your blood sugar at bedtime before an evening snack. If your reading is less than 120 mg/dL (or whatever pre-bedtime target your doctor has given you, i.e., Elizabeth, my 6-year-old's target is 140 mg/dL), you may need to eat a larger snack containing carbohydrates and protein.  For children, or those on an insulin pump, pre-bedtime target ranges may be slightly higher.  Be sure you understand what your doctor has recommended for you and if it is not working well for you be sure to consult your doctor.



You should check your blood glucose at least once during each night.  If you wake in the morning with a headache, or high fasting sugars, it may be a sign that low blood sugar occurring during the night.

If you suspect low blood glucose during the night check your blood sugar at 3:00 a.m.  If your blood glucose is low at that time, you may need a smaller dose of intermediate insulin (NPH) or long-lasting insulin (Lantus® or Ultralente) in the evening.  If you are on an insulin pump your basal rates may need adjusting.  

OH Medical Tip:  Consuming high-fat snacks late in the evening can keep blood glucose levels elevated.  




Never change your insulin guidelines without discussing it with your doctor first!  


Summary of Hypoglycemia Symptoms
(Low Blood Glucose)

Mild Hypoglycemia
Increased or sudden hunger
Feeling shaky, dizzy or nervous
Pounding heartbeat
Drowsiness, feeling tired
Sweating (cold and clammy)
Numbness/tingling around mouth
Headache or stomachache

Moderate Hypoglycemia
Any mild symptoms above, plus:
Personality change
Confusion and/or difficulty      concentrating
Slurred or slow speech
Poor coordination

Severe Hypoglycemia
***CALL 911 ASAP!***

Any of the above symptoms plus:
Loss of consciousness
Seizures and/or convulsions

Severe hypoglycemia requires injection of glucagon!




Mild Hypoglycemia

Increased or sudden hunger
Feeling shaky, dizzy or nervous
Pounding heartbeat
Drowsiness, feeling tired
Sweating (cold and clammy)
Headache or stomach ache
Numbness/tingling around mouth

Moderate Hypoglycemia
Any mild symptoms above, plus:

Personality change
Confusion and/or difficulty      concentrating
Slurred or slow speech
Poor coordination

Severe Hypoglycemia
***CALL 911 ASAP!***

Any of the above symptoms plus:

Loss of consciousness
Seizures and/or convulsions

Severe hypoglycemia requires injection of glucagon to save my life!


Islets of Hope Form PO-101

I have diabetes.  If you find me unconscious or unable to swallow please call 911 ASAP!

If I seem confused or disoriented but am able to swallow, please give me something with pure sugar like sweetened soda, juice, milk, candy, or glucose tabs which may be in my car, briefcase, pocket, or purse.

My Name is:  ____________________________________

Address:  ______________________________

Emergency Contacts:

Name                                 Phone Number




My Physician:

Other Medical Information for Paramedics: