For children who are not diabetic, the standard for hypoglycemia is below 2.8mmol/L, while diabetic children are hypoglycemic as long as their blood sugar is below 3.9mmol/L. Acute hypoglycemia may include pallor, panic, trembling of hands and feet, sweating, weakness and gastrointestinal manifestations such as nausea, vomiting and abdominal pain, and in severe cases, sudden convulsions and coma. Chronic hypoglycemia may include indifferent expression, inattention, slow reaction, abnormal behavior and mental retardation. The most common cause of hypoglycemia in children is ketotic hypoglycemia, which mostly occurs in children between the ages of 1.5 and 5 years old and is caused by eating little or not eating at dinner, prolonged starvation, difficulty in waking up from sleep the next morning or convulsions. Hypoglycemia can be caused by high insulin dosage in children with diabetes, or failure to eat in time after insulin and sudden increase in exercise.