Hypoglycemia (Low Blood Sugar) in People Without Diabetes

Symptoms

The symptoms of hypoglycemia may vary from episode to episode because low blood sugar can be mild, moderate, or severe. Increasingly severe symptoms appear as the blood sugar level falls.

In healthy people, fasting blood sugar levels are usually between 4 and 6 millimoles per litre (mmol/L).

Mild hypoglycemia

Symptoms of mild low blood sugar usually develop when blood sugar falls below 3.3 to 3.6 mmol/L and may include:

• Nausea.
• Extreme hunger.
• Feeling nervous or jittery.
• Cold, clammy, wet skin and/or excessive sweating not caused by exercise.
• A rapid heartbeat (tachycardia).
• Numbness or tingling of the fingertips or lips.
• Trembling.

Moderate hypoglycemia

If blood sugar continues to fall, the nervous system will be affected. Symptoms usually develop when the blood sugar falls below 2.8 mmol/L and may include:

• Mood changes, such as irritability, anxiety, restlessness, or anger.
• Confusion, difficulty in thinking, or inability to concentrate.
• Blurred vision, dizziness, or headache.
• Weakness, lack of energy.
• Poor coordination.
• Difficulty walking or talking, such as staggering or slurred speech.
• Fatigue, lethargy, or drowsiness.

Severe hypoglycemia

The symptoms of severe low blood sugar develop when blood sugar falls below 1.7 mmol/L and may include:

• Seizures or convulsions.
• Loss of consciousness, coma.
• Low body temperature (hypothermia).

Prolonged severe hypoglycemia can cause irreversible brain damage and heart problems, especially in people who already have coronary artery disease. If emergency medical treatment is not provided, severe hypoglycemia can be fatal.

Some medicines may mask symptoms of low blood sugar, including beta-blockers, which are often used to treat heart conditions and high blood pressure.

What to think about

Different people may develop symptoms of mild, moderate, or severe hypoglycemia at varying blood sugar levels. Although the blood sugar levels listed above are typical, they may not apply to everyone. If your blood sugar drops suddenly, you may develop symptoms even if your level is in the normal range.

A number of medical conditions can cause symptoms similar to those of hypoglycemia. Your doctor will use blood tests and other measures to make sure another condition isn't causing your symptoms.

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Author:	Caroline Rea, RN, BS, MS	Last Updated: July 13, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Alan C. Dalkin, MD - Endocrinology Donald Sproule, MD, CM, CCFP, FCFP - Family Medicine
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