Your body normally maintains your blood sugar level within a carefully controlled range, constantly adjusting for changes from eating and energy use. If your blood sugar drops below this range, you begin to experience the signs of low blood sugar, or hypoglycemia. Hypoglycemia has a variety of causes that usually require medical evaluation for diagnosis.
Blood Sugar Metabolism
Carbohydrates in your food are broken down and absorbed as simple sugars. The most common of these is glucose, which serves as your body's primary energy source. When your blood glucose level rises after eating, your pancreas releases insulin that signals your cells to absorb more glucose for immediate energy and storage. As your blood glucose level then drops in response, the pancreas switches from insulin to glucagon release. Glucagon directs your cells to stop taking up glucose and instead release their stored glucose to keep your blood sugar from dropping too low. This give and take between eating, physical activity, insulin and glucagon goes on 24 hours a day to keep your blood glucose between 70 and 99 mg/dl, according to Lab Tests Online. Any imbalance in this system can lead to abnormal blood sugar levels, including hypoglycemia.
Signs of Hypoglycemia
When your body cannot stop your blood glucose level from dropping too low, hypoglycemia results. Low blood sugar can occur suddenly but usually is mild and short-lived. Common symptoms consist of shakiness, anxiety, sweating, light-headedness, confusion and weakness. More severe symptoms include blurred vision, seizures, heart palpitations and unconsciousness. If you become hypoglycemic while sleeping, you can experience nightmares or crying out, waking to your pajamas and bedding damp from sweat, or feeling tired and confused upon waking. None of these symptoms is particular to hypoglycemia, but can occur with many other disorders.
Causes of Hypoglycemia
Hypoglycemia in adults and adolescents usually is a side effect of diabetes medication, but other medical disorders also can be the cause, according to the National Diabetes Information Clearinghouse. Because diabetes medications are intended to lower blood glucose levels, hypoglycemia can result from too much medication or if you eat too little, do extra physical activity or drink too much alcohol while taking these medications. Hypoglycemia in non-diabetics is commonly divided into reactive and fasting categories. Reactive hypoglycemia occurs within four hours of eating and is incompletely understood, but possibly relates to your metabolism overreacting to hormonal signals such as epinephrine. Fasting hypoglycemia occurs unrelated to meals and is commonly linked to medications, alcohol use, critical illnesses, certain hormonal disorders and insulin-producing tumors.
Evaluation for Hypoglycemia
Your body's glucose metabolism is complex and the list of possible disorders affecting it is extensive. Confirming that hypoglycemia causes your symptoms is the first step, which generally requires meeting three criteria known as Whipple's triad: having the symptoms of hypoglycemia, documenting a low glucose level in blood drawn while these symptoms are occurring and having the symptoms disappear when your glucose level recovers. Once the diagnosis of hypoglycemia is confirmed, you can begin to work with your health care provider to determine the underlying cause of your low blood sugar.
