A microsleep is an episode of sleep which may last for a fraction of a second or up to thirty seconds. Often, it is the result of sleep deprivation, mental fatigue, depression, or hypersomnia. For the sleep-deprived, microsleeping can occur at any time, typically without substantial warning.
“微睡眠”指持续时间不超过30秒的短暂睡眠状态,多由睡眠不足、精神疲乏、抑郁、或嗜睡症引起。对那些睡眠不足的人来说,随时都可能进入微睡眠状态,而且没有任何征兆。

Microsleeps become extremely dangerous when they occur in situations which demand constant alertness, such as driving a motor vehicle or working with heavy machinery. People who experience microsleeps usually remain unaware of them, instead believing themselves to have been awake the whole time, or to have temporarily lost focus.
在驾驶摩托车,或是进行重型机械作业等需要高度警醒的工作中,出现微睡眠状况是极度危险的。经历过微睡眠状况的人通常都对此毫不察觉,他们以为自己一直处于清醒状态,或者认为自己只是偶尔走神了。

When experiencing microsleeps while driving an automobile, from the perspective of the driver, he or she drives a car, and then suddenly realizes that several seconds have passed by unnoticed. It is not obvious to the driver that he or she was asleep during those missing seconds, although this is in fact what happened. The sleeping driver is at very high risk for having an accident during a microsleep.
开车时出现微睡眠状况,从司机的角度来看,他/她正开着车,好像突然有那么几秒钟一下子跳过去了。司机本人可能没有意识到在这几秒钟里他是出于睡眠状态的,但他的确是睡着了。开车时出现微睡眠状况极易发生意外。