What Is Considered Low Blood Sugar?

Sugar or glucose is considered as a major raw material in the production of chemical energy that powers all the activities of body cells. A condition called hypoglycemia or low blood sugar occur when the level of glucose in the blood is not enough to effectively fuel body cells. Generally, what is considered low blood sugar is below 70 mg/dl (milligrams of glucose per deciliter of blood) and what is considered normal blood sugar level is within the range of 70-100 mg/dl. The symptoms of hypoglycemia may occur at levels below 60 mg/dl. Brain functions can be seriously affected if the blood sugar level is below 50 mg/dl.

There are controversies involved as to what is considered low blood sugar. The level of blood sugar low enough to be considered hypoglycemia may be different for different people, in different circumstances, and for different purposes. Although the lower limit of blood sugar is 60 or 70 mg/dl, there are people whose blood sugar level is below this range but do not show any symptoms or disease. Moreover, the normal blood glucose level of children is slightly lower than adults. Because of these controversies, the Endocrine Society recommends that a diagnosis of hypoglycemia as a problem for an individual person be based on the combination of low blood glucose level and the occurrence of adverse symptoms.

Hypoglycemia is more common to people with diabetes. Diabetes is a metabolic disorder in which there is no control of blood sugar, through inadequate insulin production (type 1) or decreased sensitivity to insulin (type 2) causing kidney, eye, and nerve damage.

Symptoms of Low Blood Sugar (Hypoglycemia)

low blood sugar (Image from CDC)

Most of the early symptoms of hypoglycemia are caused by epinephrine, one of the major hormones released during hypoglycemia. Common symptoms include trembling/shaking, anxiety, weakness, palpitations, hunger, irritability, sweating, pupil dilation, and clummy or jerky skin. Serious symptoms of hypoglycemia occur when the brain remains deprived of glucose; these are headache, confusion, thinking difficulty, seizures, and coma. Death can occur after significant trauma and loss of consciousness.

Causes of Low Blood Sugar (Hypoglycemia)

Hypoglycemia has different causes: alcohol intake; missed meals; use of medications such as beta-blockers, pentamidine, trimethoprin, and trimethoprin; severe infection; overmedication of insulin or antidiabetic drugs; liver failure; kidney failure; insufficiency of adrenal hormones such as cortisol and epinephrine; deficiency of growth hormones such as those produced by the pituitary gland; loss of appetite; delayed insulin release after a meal has been absorbed; congenital hyperinsulinism or defect in the regulation of insulin; abnormal increase in insulin (insulinoma) because of insulin-producing tumors (usually developed in the pancreas).

Diagnosis of Hypoglycemia

Endocrinologists use the Whipple’s triad to determine whether a person’s symptoms are due to hypoglycemia. The Whipple’s triad has three conditions:

  1. The person shows the known symptoms of hypoglycemia.
  2. The blood glucose level of the person is low at the time the symptoms occur.
  3. The symptoms of the person improved or reversed when the blood glucose is restored to normal.