Hypoglycemia: Definition and Overview

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Hypoglycemia: Definition and Overview

What is hypoglycemia?

Hypoglycemia is a situation in which blood sugar too low to fuel the body’s activities. The normal range for blood sugar is about 60 mg/dl (milligrams of glucose per deciliter of blood) to 120 mg/dl, depending on when a person last ate. If a person has not eaten for many hours, blood sugar can occasionally fall below 60 mg/dl or even below 50 mg/dl without indicating a serious abnormality or disease.

Individuals who take insulin, which includes all people with Type 1 (insulin-dependent) diabetes and some people with Type 2 (non-insulin-dependent) diabetes, are prone to hypoglycemia. People with Type 2 diabetes who take sulfonylureas are also vulnerable to episodes of low blood sugar. Hypoglycemia can occur when a person takes too much medicine, skips or delays a meal, eats too little food for the amount of insulin he injected, exercises too strenuously, or drinks too much alcohol.

What are the symptoms of hypoglycemia?

Common symptoms of hypoglycemia include weakness, drowsiness, confusion, hunger, dizziness, paleness, headache, irritability, trembling, sweating, rapid heartbeat, and a cold, clammy feeling. In severe cases, hypoglycemia can cause a person to lose consciousness or even lapse into a coma.

How to treat hypoglycemia

Most people with diabetes can recognize these symptoms and treat them by quickly eating or drinking something with sugar, such as candy, juice, or a regular (not diet) soft drink, or by taking special glucose tablets or gel, available over the counter in pharmacies. However, some people with long-standing diabetes develop a condition known as hypoglycemia unawareness or hypoglycemia without warning, in which they no longer develop the usual symptoms that herald the onset of hypoglycemia. This condition can be reversed by maintaining higher blood sugar levels for a short period of time (about two weeks) and scrupulously avoiding low blood sugar.


If a person with diabetes does not recognize and treat hypoglycemia by eating something, he may require a glucagon injection (which must be given by another person). Glucagon, a hormone, quickly eases the symptoms of hypoglycemia by converting liver stores of glucose into a usable form and releasing it into the bloodstream. A person who does not respond immediately to treatment for hypoglycemia may need to be admitted to the hospital so that blood sugar can be stabilized.

People with diabetes can reduce or prevent episodes of hypoglycemia by monitoring their blood sugar levels frequently and learning to recognize the symptoms of low blood sugar and the situations that can trigger it. They should consult their health-care providers for advice about the best way to treat low blood sugar. Friends and relatives should be informed about the symptoms of hypoglycemia and know how to treat it, if necessary.

Originally Published May 18, 2006


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