The chill that sends people running from a “haunted” room may start not with spirits, but with a vibration too low for human ears to catch.

A new study highlighted by reports indicates that infrasound — sound below 20 hertz — likely plays a major role in some alleged hauntings. Researchers found that these low-frequency vibrations can raise cortisol levels in saliva and increase irritability, two measurable changes that could sharpen unease and make ordinary sensations feel ominous. The finding gives a physiological edge to a debate that usually drifts into folklore.

Key Facts

  • Infrasound refers to sound below 20 Hz, beneath normal human hearing.
  • The study links infrasound exposure to higher cortisol levels in saliva.
  • Researchers also observed increased irritability.
  • The findings suggest a physical explanation for at least some haunting reports.

The implications stretch beyond ghost stories. Old buildings, rumbling pipes, ventilation systems, and heavy machinery can all produce low-frequency vibrations. In places already primed by expectation, that hidden acoustic pressure may shape how people interpret stress, discomfort, or a sense that something feels deeply wrong. Reports suggest the environment itself may supply the fear, then let the imagination do the rest.

If infrasound changes stress chemistry and mood, some “paranormal” experiences may begin as a building problem, not a supernatural one.

That does not mean every unexplained account now has a tidy answer. It does mean technology and physiology offer a stronger framework for testing claims that once lived mostly in anecdote. A measurable stress response gives investigators something concrete to track, compare, and challenge. For readers, the bigger lesson feels simple: the body can react to forces the mind never consciously registers.

What happens next matters because the research could reshape how people assess so-called haunted spaces — and how architects, engineers, and health experts think about indoor environments. Future work will need to test where infrasound appears, how much exposure matters, and which settings trigger the strongest effects. If those answers hold up, the ghost hunt may turn into something more practical: a search for the hidden vibrations rattling both buildings and nerves.