What is Hyperglycemia? Find Information about Hyperglycemia

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What is Hyperglycemia?

Hyperglycemia is high blood glucose (sugar). Glucose levels increase when the body doesn’t have enough insulin or when the body doesn’t use insulin properly. It is a condition that can lead to serious complications if not treated appropriately.

There are two types of hyperglycemia that can occur in people with diabetes:

• Fasting (for at least 8 hours) - glucose level is higher than 130 mg/dL.

• Postprandial (1-2 hours after a meal) - glucose level is usually higher than 180 mg/dL.

People who do not have diabetes normally do not go over 140 mg/dL 1-2 hours after a meal. However, it is possible to reach up to 180 mg/dL after eating a large meal. Consistently high levels like this can put a person at risk of developing type II diabetes.


Failure to take an adequate amount of insulin or glucose-lowering medicine can cause hyperglycemia. Doses normally need to be increased (depending on glucose results) when consuming large amounts of food/carbohydrates, when inactive more than usual or not exercising enough, during an acute infection or illness, and for emotional stress, pregnancy, or injury.

Symptoms & Complications

Hyperglycemia symptoms include increased thirst (polydipsia), frequent urination (polyuria), blurred vision, fatigue, and trouble concentrating.

Uncontrolled diabetes can lead to nerve, blood vessel, and organ damage. It can affect vision, prolong wound healing (especially in the lower extremities), and cause erectile dysfunction.

A serious and life-threatening complication (mostly in type I diabetes) is ketoacidosis. This occurs when glucose can no longer provide energy (because of the absence of effective insulin) so the body’s fat is metabolized to produce energy. Ketones are produced as a waste product from the conversion of fat to energy. When the body is unable to get rid of all the ketones (through the urine) and they build up in the blood, ketoacidosis can occur. Symptoms include shortness of breath, sweetish odor (fruity) of the breath, low blood pressure, weak, thready pulse, stupor, and coma.


Now that you know “what is hyperglycemia” and how serious it can be, let us look at what can be done to keep glucose levels under control so future complications can be prevented.

Preventive measures include:

  • monitoring blood glucose levels as directed by a health care provider
  • following a prescribed diet
  • exercising regularly
  • taking insulin or glucose-lowering medicine as ordered.

Note: People with type I diabetes who have a blood glucose over 240 mg/dL, need to check their urine for ketones. If the urine is positive for ketones, one should not exercise because this can cause levels to go even higher. People with type II diabetes who have a glucose level over 300 mg/dL (with or without ketones) should not exercise.

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