The Sleep Disorder That Sounds Like Gunfire

Somewhere between wide awake and fully asleep, a small number of people hear something that shouldn't be there. It sounds like a gunshot, a bomb, or a slamming door, and it seems to come from inside their own skull.

This condition has an official medical name: Exploding Head Syndrome. Despite the alarming title, doctors classify it as a type of parasomnia, the same broad category that covers sleepwalking and night terrors.

The sound itself isn't real in the sense that nothing physically happened in the room. It's generated entirely by the brain during the transition into or out of sleep, often in that fuzzy in-between state called the hypnagogic period.

Researchers believe it may happen when the brain's neurons fire in a burst as it's shutting down for the night, almost like a system glitch during a power-down sequence. The auditory cortex briefly misfires, and the brain interprets that surge as an explosive noise.

Studies estimate that up to 10 to 15 percent of people may experience it at least once in their lives, though many never mention it because it sounds too strange to bring up. Some people have episodes just once, while others report them recurring for years.

The good news is that the episodes are almost always painless. There's no actual injury happening, just a jarring sensory experience that can leave someone's heart racing and wide awake for a few minutes afterward.

Doctors still don't fully understand why it happens to some people and not others, though stress, fatigue, and irregular sleep schedules seem to make episodes more likely. For most people, the syndrome is a bizarre but harmless quirk of the sleeping brain, not a warning sign of anything more serious.