Jake hadn't eaten since breakfast — he'd just been too busy. As he headed off to wrestling practice, he felt like he was running out of energy, so he grabbed some mini donuts from the vending machine. Two hours later, Jake felt dizzy and shaky, and he was starting to get a headache. Jake had felt this way before, and one of his friends said he might have hypoglycemia. But when Jake visited his doctor, she told him that it was unlikely.

Lots of people wonder if they have hypoglycemia (pronounced: hy-po-gly-see-mee-uh), but the condition is not at all common in teens. Teens who do have hypoglycemia usually have it as part of another health condition, such as diabetes.

What Is Hypoglycemia?

The body's most important fuel is glucose, a type of sugar. When you digest most foods, sugar is released, and that sugar ends up in your bloodstream as glucose. Your body, particularly your brain and nervous system, needs a certain level of glucose to function — not too much, and not too little. If your blood glucose level isn't right, your body will react by showing certain symptoms.

Hypoglycemia occurs when a person's blood sugar levels are abnormally low, and it's a potentially serious condition. If you know someone who has diabetes, you may have heard them talk about "insulin shock," which is the common name for a severe hypoglycemic reaction.

People with diabetes may experience hypoglycemia if they don't eat enough or if they take too much insulin — the medicine most commonly used to treat diabetes in kids.

What Are the Symptoms of Hypoglycemia?

Some symptoms of hypoglycemia are caused when the body releases extra adrenaline (epinephrine), a hormone that raises blood sugar levels, into the bloodstream to protect against hypoglycemia. High blood levels of adrenaline can make the skin become pale and sweaty, and a person can also have symptoms such as shakiness, anxiety, and heart palpitations (a fast, pounding heartbeat).

Other symptoms of hypoglycemia are caused when not enough glucose gets to the brain; in fact, the brain is the organ that suffers most significantly and most rapidly when there's a drop in blood sugar. These symptoms include headache, extreme hunger, blurry or double vision, fatigue, and weakness. At its most severe, insufficient glucose flow to the brain can cause confusion, seizures, and loss of consciousness (coma).

Who Gets Hypoglycemia?

Almost all teens who take blood sugar-lowering medicine for diabetes get hypoglycemia from time to time. Insulin moves sugar out of the blood and into the body's cells, where it's used as a fuel. Someone with diabetes who takes too much insulin or doesn't eat enough food to balance the effects of insulin may have a drop in blood sugar.

Hypoglycemia related to not eating rarely occurs in teens and adults unless the starvation is severe, as in anorexia.

Poisoning or overdoses of some substances, such as alcohol, or certain drugs, like insulin or other diabetes medications, can cause some otherwise healthy people to develop hypoglycemia. People with certain types of cancer or severe chronic illness also can get hypoglycemia. There are also rare genetic forms of hypoglycemia, but the symptoms are severe and almost always begin in infancy.

If hypoglycemia is so rare among people in their teen and adult years, why do a lot of people think they have it?

There are a couple of reasons. For one thing, the symptoms that occur with hypoglycemia overlap with those that people can have for many other reasons — or no reason at all. It's normal to feel fatigue, weakness, or have a headache periodically, especially if someone has had a stressful day or too little sleep. And drinking a lot of coffee, cola, or other caffeine-containing beverages can certainly make a person feel a bit shaky or jittery.

Also, it seems that some people's bodies react differently to eating high amounts of sugar than others. When these people eat meals that contain lots of sugar and starch — like Jake did when he grabbed the donuts — the rise and fall of blood sugar that results can trigger hypoglycemia-like symptoms, even though the blood sugar doesn't actually drop to below-normal levels.

How Is Hypoglycemia Diagnosed?

A doctor who thinks a person might have hypoglycemia will ask about the patient's medical history and diet, in particular about the timing of the symptoms, whether they tend to occur after eating high-sugar meals, and if the symptoms go away quickly with eating sugar.

The only way to tell for sure whether someone's symptoms are related to hypoglycemia is to test the blood sugar while the person is having the symptoms. If such a test shows that the blood sugar is truly low, the doctor may do other tests to diagnose specific diseases that can cause hypoglycemia.

How Is Hypoglycemia Treated?

The treatment of hypoglycemia depends upon its cause. If you're otherwise healthy and you notice occasional hypoglycemia-like symptoms, you might try eating a diet that's lower in simple sugars and/or cutting down on your caffeine intake. If this doesn't make the symptoms go away, be sure to talk with your doctor.

Reviewed by: Steven Dowshen, MD
Date reviewed: October 2010