Hypoglycemia means that blood levels of glucose are too low. This condition is most commonly a complication of treatment for diabetes. Symptoms of hypoglycemia vary among people. When blood sugar levels drop, symptoms can include trembling, anxiety, palpitations (fast or pounding heartbeat), sweating, clammy skin, and hunger. These are among the early symptoms of hypoglycemia. Other possible symptoms can be dizziness, chills, nausea, and lack of coordination. If the low blood sugar levels persist, more serious symptoms develop, such as headache, confusion, difficulty with thinking, and seizures. Eventually, coma may develop.