What are symptoms of hypoglycemia and how low is too low?
The normal range of glucose in the bloodstream is from 70 to 100 mg/dL when the individual is fasting (that is not immediately after a meal). The body's biochemical response to hypoglycemia usually starts when sugars are in the high/mid 70's. At this point, the liver releases its stores and the hormones mentioned above start to activate. In many people, this process occurs without any clinical symptoms. The amount of insulin produced also declines in an attempt to prevent a further drop in glucose.
While there is some degree of variability among people, most will usually develop symptoms suggestive of hypoglycemia when blood glucose levels are lower than 50 mg/dL. The first set of symptoms are called adrenergic (or sympathetic) because they relate to the nervous system's response to hypoglycemia. Patients may experience any of the following;
- intense hunger,
- palpitations, and
- often have trouble speaking.
In most people, these symptoms are easily recognizable. The vast majority of individuals with diabetes only experience this degree of hypoglycemia if they are on medications or insulin. People (with diabetes or who have insulin resistance) with high circulating levels of insulin who fast or change their diet to lower their carbohydrate intake drastically should also be cautioned. These individuals may also experience modest hypoglycemia.
People being treated for diabetes who experience hypoglycemia may not experience symptoms as easily as people without diabetes. This phenomenon has been referred to as hypoglycemic unawareness. This can be dangerous as blood sugars may approach extremely low levels before any symptoms are perceived.
Anyone who has experienced an episode of hypoglycemia describes a sense of urgency to eat and resolve the symptoms. And, that's exactly the point of these symptoms. They act as warning signs to tell the body to consume more fuel. At this level, the brain still can access circulating blood glucose for fuel. The symptoms provide a person the opportunity to raise blood glucose levels before the brain is affected.
If a person does not or cannot respond by eating something to raise blood glucose, the levels of glucose continue to drop. With further drops in blood glucose, patients progress to neuro-glyco-penic ranges (meaning that the brain is not getting enough glucose). At this point, symptoms progress to confusion, drowsiness, changes in behavior, coma, and seizure.