A low blood glucose level (<50 mg/dl or 3.3 mmol/L) that occurs after bedtime. It may be asymptomatic, or it may cause nightmares, night sweats, other sleep disturbances, tachycardia, convulsions, or, rarely, death. It typically results from relatively high levels of insulin in insulin-treated diabetic patients. It may be prevented by consuming a bedtime snack or by adjusting evening doses of insulin based on bedtime blood glucose levels.