Microsleep refers to brief episodes of sleep (30 seconds or less) where the eyes close and the brain function lapses into unconsciousness. Many people do not even recognize these occurrences and believe themselves to have been completely awake. This can be brought on by sleep deprivation or monotonous tasks. The outward signs of these episodes are droopy eyes, slow eye blink response, and head-nodding. Most adults have experienced these types of episodes while being a passenger in a car, reading a dull book, or watching television after a large meal. Microsleep episodes by themselves are harmless. However, microsleep can be very dangerous in situations that require constant attention such as while driving a car or working with heavy equipment.