Hypoglycemia, or abnormally low blood sugar, is caused by the impaired response (or failure) of the liver to release glucose as blood sugar levels decrease. The imbalance in the rate of glucose released from the liver and its use by other body tissues can result in the following hypoglycemic symptoms: hunger, nervousness, dizziness, confusion, sleepiness, difficulty speaking, feeling anxious or weak, irritability, sweating, loss of consciousness, and increased blood pressure. In diabetic individuals, too much insulin, limited or delayed food intake, a sudden increase in exercise, and excessive alcohol ingestion cause fasting hypoglycemia. Reactive hypoglycemia, however, occurs about four hours after a meal. The cause is unknown, but experts speculate that deficiencies in the release of glucagon (hormone released by the pancreas to increase blood glucose levels) and sensitivity to epinephrine (hormone released by the adrenal glands) contribute to hypoglycemia.
Normal blood sugar levels range from 70 to 110 mg/dl (milligrams per deciliter) upon waking and 70 to 140 mg/dl following meals. For those with diabetes, blood glucose levels before meals should be between 90 mg/dl and 130 mg/dl. One to two hours after a meal, blood glucose values should be less than 180 mg/dl. A blood sugar level of 70 mg/dl or less is defined as hypoglycemia. Severe hypoglycemia occurs when values are less than 40 mg/dl. Diagnosis of hypoglycemia requires fasting blood glucose values of less than 50mg/dl or of blood glucose values less than 70 mg/dl after ingesting food or drink. Treatment for hypoglycemia involves administering sugar in the form of glucose tablets, fruit juice, regular soft drinks, milk, hard candy, honey, or sugar. Hypoglycemia is prevented with regular meals and limiting alcohol and caffeine intake.
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American Diabetes Association. "Tight Diabetes Control." Available from <http://www.diabetes.org>
National Institute of Diabetes and Digestive and Kidney Diseases. "Hypoglycemia." Available from <http://www.niddk.nih.gov>
National Library of Medicine. "Diabetes." Available from <http://www.medlineplus.gov/>