What is a microsleep?

• A. A brief involuntary lapse into sleep, usually under 15 seconds
• B. A conscious nap lasting several minutes
• C. A phase of deep sleep during wakefulness
• D. A trick of perception during fatigue

Answer: (A)

Microsleep is a brief, involuntary episode of sleep that occurs while you are supposed to be awake. It typically lasts only a few seconds, usually under 15 seconds, before you return to activity. Because it happens without deliberate intent and often during fatigue or monotonous tasks, you may not realize it’s happening, even though your brain has briefly fallen asleep. This can seriously impair attention and reaction time, which is why it’s especially important in aviation where continuous vigilance is critical. It’s not a conscious nap lasting several minutes, nor a phase of deep sleep during wakefulness, and it isn’t simply a perceptual illusion—it’s genuine sleep that intrudes briefly and then ends, with normal wakefulness resuming afterward.