What Is Hypoglycemia? - Definition, Symptoms, Causes & Treatment

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  • 0:04 Hypoglycemia
  • 0:39 Glucose Levels
  • 1:33 Early Symptoms
  • 2:23 Causes & Triggers
  • 3:12 Treatment Options
  • 4:34 Lesson Summary
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Lesson Transcript
Instructor: Kiley Griffin
In the following lesson, you'll learn about hypoglycemia, including its role in diabetes, its causes and treatment, and why it's important to manage symptoms immediately.


Joe was recently diagnosed with diabetes and is learning how it affects his body. Joe has started to exercise, as instructed by his doctor, but often feels lightheaded after going for a light jog. His doctor told him that this might happen and to make sure that he has some juice or soda with him to drink when he feels this way. Joe's doctor thinks it's probably hypoglycemia, but Joe isn't sure what that has to do with his diabetes. Hypoglycemia is low blood sugar, or blood glucose. The body needs glucose, or sugar, for energy, which comes from the carbohydrates we eat.

Glucose Levels

Extra glucose is stored in the muscles and liver for later use by the body. The liver releases this extra glucose if a person's blood sugar begins to fall, in order to keep sugar levels balanced in the body. For some people, especially those with diabetes, this doesn't always work. Their blood sugar will remain low, causing hypoglycemia.

When glucose levels increase, insulin is released by the pancreas and the extra glucose enters the liver where it's stored for later use. In people with normal functioning systems, if their blood sugar begins to drop, a hormone called glucagon is released, which signals the liver to release the stored glucose to regulate their blood sugar. Normal glucose levels are between 70 and 100 milligrams per deciliter; diabetics should check their blood sugar levels frequently to ensure that they're within the normal range and adjust food, insulin, and medications accordingly.

Early Symptoms

Each person who experiences hypoglycemia will have different symptoms. Identification of early symptoms is important for treatment purposes. If hypoglycemia goes untreated, it can lead to more serious and even life-threatening symptoms.

Early symptoms of hypoglycemia include hunger, shakiness, dizziness, and irritability. Some individuals may experience nausea, fatigue, and chills. When an individual at risk for hypoglycemia develops any of these symptoms, they should take action immediately to raise their blood sugar.

More serious symptoms of hypoglycemia include lack of coordination, blurred vision, headache, and fainting. Seriously low blood sugar can also lead to seizures, unconsciousness, and coma if left untreated, a situation requiring emergency medical care.

Causes & Triggers

Hypoglycemia occurs most often in people with diabetes, although it can also occur in people taking certain medications. Medications that are used to control blood sugar in people with diabetes can cause side effects, including low blood sugar. Insulin controls blood sugar, so if there's not enough insulin, blood sugar levels can rise. Diabetics often need to inject insulin into their bodies to regulate the process.

In people who have diabetes, diet and exercise can also trigger hypoglycemia. If a diabetic is taking insulin and takes too much after a meal, it can cause hypoglycemia. It can also occur after skipping a meal, not completely eating a meal, or eating a meal high in sugar. Diabetics who over-exercise may deplete the blood sugars needed to regulate the body, causing blood sugar levels to drop.

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