There is something deeply unsettling about walking into a room and feeling, for no apparent reason, a creeping sense of dread.
No flickering lights, no strange noises, nothing you can point to. Just a feeling.
Scientists may finally have an explanation, and it has nothing to do with the supernatural.
A new study published in Frontiers in Behavioral Neuroscience suggests that infrasound, a type of sound so low in frequency that human ears cannot consciously detect it, may be quietly messing with your mood, making you irritable, sad, and stressed without you ever realising why.
WHAT EXACTLY IS INFRASOUND?
Sound travels in waves, and the number of waves per second is called its frequency, measured in hertz (Hz).
Human hearing typically picks up sounds between 20 Hz and 20,000 Hz.
Infrasound sits below that threshold, under 20 Hz, which means your ears technically cannot hear it.
But that does not mean your body is ignoring it.
Infrasound is everywhere. It is produced by wind turbines, air conditioning units, ventilation systems, heavy traffic, and even the rumble of building pipes.
It occurs naturally too, generated by earthquakes, volcanoes, and storms. You are probably surrounded by it right now.
CAN INFRASOUND ACTUALLY AFFECT YOUR MOOD?
Researchers at MacEwan University in Canada conducted a controlled experiment with 36 participants.
Each person was placed in a room and exposed to either calming or unsettling music, with infrasound at approximately 18 Hz either present or absent in the background.
Crucially, no one was told whether the infrasound was switched on.
The results were striking. Participants exposed to infrasound reported feeling more irritable, less interested in what they were hearing, and rated the music as sadder, regardless of whether the music was designed to be calming or creepy. More tellingly, their saliva samples revealed elevated levels of cortisol, the body’s primary stress hormone, after infrasound exposure.
None of them consciously detected the infrasound. Not one participant could reliably tell whether it was present. Yet their bodies responded anyway.
IS THIS WHY SOME PLACES FEEL HAUNTED?
This is where it gets interesting. Researchers have long theorised that infrasound could explain why certain buildings feel eerie.
Old churches, industrial sites, and basements with humming machinery are all common sources of low-frequency sound energy.
Previous investigations have suggested that infrasound around 18 to 19 Hz could cause visual disturbances and feelings of unease, precisely the sensations people associate with ghostly encounters.
The new study does not claim to have debunked ghosts. But it does suggest that infrasound, invisible and inaudible, may be generating genuine emotional and physiological responses that people misattribute to other causes.
SHOULD YOU BE WORRIED ABOUT INFRASOUND?
The study’s authors are careful to note that this was a short-term exposure in a controlled setting. The sample size was small and predominantly female, so broader conclusions need more research.
What the findings do highlight, however, is that infrasound in urban environments deserves far more attention as a potential public health concern.
If a barely detectable hum in the walls can raise your cortisol and darken your mood, it is worth asking what months or years of such exposure might do.
Your house may not be haunted. But it might be talking to you in a language your ears were never built to understand.
