The symptoms of hypoglycemia, or low blood sugar, include hunger, dizziness, weakness, drowsiness, rapid heartbeat, clamminess, paleness, irritability, shakiness and sweating, according to WebMD. People with extreme cases can become unconscious, and sometimes a coma can result.
Hypoglycemia symptoms may be very similar to the symptoms of other unrelated conditions. Overproduction of catecholamines, which is sometimes caused by anxiety or stress, is one such condition where symptoms are often mistaken for hypoglycemia.
When blood levels of glucose, the sugar the body uses for its main energy source, are so low that they can no longer fuel activities, hypoglycemia results. Usually, the amount of blood sugar, or glucose in the bloodstream, at any time is between 60 milligrams to 120 milligrams per deciliter of blood. Under some conditions, such as when fasting, this amount can drop below 60 or even 50 milligrams per deciliter, but anything below 45 mg/dL is considered abnormal and usually indicates a serious condition.
Hypoglycemia is most often caused by diabetes, according to WebMD. In this case, the body is unable to produce effective amounts of the hormone insulin, which regulates the amount of glucose present in the blood and helps to get the glucose into the cells. Hypoglycemia can also occur as a result of alcohol abuse, during early pregnancy, during extended, heavy exercise and during long-term fasting.