Most people have walked into a room in an old building and felt, for no good reason, like something was off. Not scary in a movie way. More like the air in the room had an opinion about them being there. The mood dips. The neck prickles. There is no visible cause, no sound, no draft, just an unshakeable sense that the space itself is communicating something the brain cannot quite translate. People usually chalk it up to old houses having old vibes, or to the power of suggestion after hearing the building had a history. They move on. They do not think much more about it.
Except researchers have been thinking about it quite a bit. And in the spring of 2026, a team based in Canada published findings that might explain what is actually happening in those rooms. The answer does not involve anything supernatural. It involves sound waves your body can detect but your ears cannot hear.
The question is not whether the experience is real. The experience is real. The question was always what was producing it.
What Infrasound Actually Is
Infrasound describes sound wave frequencies below 20 Hz, which are typically imperceptible to humans. Think of the lowest possible note on a pipe organ, and then go lower, past the point where it registers as sound at all, until it is simply a vibration moving through the air and through you. It can come from natural sources like storms, or from human-made sources like traffic. It is also, as it turns out, produced reliably by something far more domestic: old buildings.
According to a 2026 study in Frontiers in Behavioral Neuroscience, infrasound “is pervasive in everyday environments, appearing near ventilation systems, traffic, and industrial machinery,” and many people are exposed to it without knowing. The study was led by Prof. Rodney Schmaltz of MacEwan University in Canada, who specializes in pseudoscience and misinformation. The particular detail that catches the imagination is that a creaking, allegedly spooky old building, the kind with a boiler that groans and pipes that knock and a basement nobody visits twice, is practically a factory for producing this stuff.
Past research supports this, including a notable incident from decades ago when a British engineer named Vic Tandy began noticing odd shapes at the corners of his vision while working in a laboratory at a medical equipment company. Coworkers had long said the building was haunted. But Tandy’s visions disappeared soon after he discovered and disabled a nearby fan that had been generating infrasound rumblings, according to Gizmodo’s coverage of the new research. The ghost was a broken ventilation system. Which is both a relief and, somehow, also worse.
What the New Study Found
Researchers recruited 36 participants for a controlled lab experiment. All of the volunteers were told to sit in a room while listening to either relaxing or creepy music. Half of the volunteers were also exposed to infrasound at 18 Hz, provided by hidden subwoofers. Compared to control subjects, people exposed to infrasound reported feeling more irritable and experienced higher cortisol levels.
That last part is the one worth paying attention to. Cortisol is your body’s primary stress hormone, the internal alarm system that fires when something feels wrong – a smoke detector for the nervous system that does not always know the difference between a real threat and an old furnace. As Schmaltz noted, “the body can respond to infrasound even when we can’t consciously hear it.” Participants could not reliably identify whether infrasound was present, and their beliefs about whether it was on had no detectable effect on their cortisol or mood. In other words, their rational minds had no vote. The stress response happened anyway.
Prof. Trevor Hamilton of MacEwan University explained that elevated cortisol “helps the body respond to immediate stressors by inducing a state of vigilance,” an evolutionarily adapted response that helps in many situations. “However, prolonged cortisol release is not a good thing. It can lead to a variety of physiological conditions and alter mental health.” Translation: your body treating a Victorian-era boiler like a predator crouching in tall grass is not great for you long-term, especially if you happen to work in an old building or live in one.
The mood findings were almost as striking. Participants were unable to tell when the infrasound waves were being emitted, but they acted more irritated and unsettled when they were, regardless of what music was playing. They also tended to rate both kinds of music as sadder than the participants who were not exposed to infrasound. The same song, objectively, just rated as more melancholy when the invisible low-frequency hum was running underneath it. Home decor gets away with a lot, but apparently so does plumbing.
How the Brain Fills in the Blanks
Here is where it gets genuinely interesting, and where the research moves from “neat lab finding” into something with real implications for how human perception actually works. The researchers were not just studying infrasound. They were studying the story the mind tells when the body registers distress it cannot explain.
Schmaltz told The Guardian: “What infrasound may do is supply a bit of bodily discomfort that a ghost or haunting explanation can then attach itself to. For someone who is not inclined to think in terms of ghosts, the same sensation would probably just register as a stuffy, uncomfortable old building. For someone who is already primed, it might feel like proof of a spirit or presence.”
This is the brain doing exactly what it is built to do. When your body sends up a distress signal, your brain goes looking for a cause. If there is no visible, audible, or logical cause available, the brain does not simply shrug and log it as a mystery. It reaches for whatever framework is already loaded, whether that is “old house = haunted” or “that basement gives me a bad feeling” or “something is off here and I am leaving.” The infrasound does not create the belief. It creates the feeling that the belief then comes to explain.
Researchers believe the cortisol spike is an evolutionary adaptation that induces a state of vigilance in response to environmental stressors we cannot see, such as distant storms or large predators. The frequency range that infrasound occupies is the same range produced by some of the things humans have historically needed to be afraid of, the subsonic rumble before an earthquake, the barely-perceptible vibrations that travel ahead of a large animal approaching through dense forest. The body learned to listen before the ears could.
A Country Full of Unexplained Feelings
A 2025 YouGov poll found that 60 percent of Americans say they have had at least one paranormal experience, with the most common being feeling a presence or unknown energy, at 35 percent. That is a significant portion of the population having an experience real enough to remember and report, anchored not to any visual or auditory hallucination but to a felt sense of presence. Which, given what the MacEwan study found, is worth placing next to the infrasound data for a moment.
A 2025 Gallup poll found that 39 percent of Americans express a belief in ghosts, while 48 percent believe in psychic or spiritual healing. Belief and experience are not the same thing, and the research is not arguing that every person who has felt a presence was standing near a rattling pipe. But the overlap between “felt an unknown energy” and “was probably experiencing cortisol-mediated stress from an inaudible environmental source” is not nothing. It is, if anything, a slightly more humanizing explanation than dismissing those experiences as pure imagination.
People are not making things up. Their bodies are responding to something real. The interpretation is where the story diverges.
What This Does and Doesn’t Explain
The researchers are careful, appropriately so, not to overstate the case. Schmaltz noted clearly that “infrasound does not cause people to believe they have seen a ghost. What it might do is provide unexplainable discomfort, which some people may then attribute to a ghost or haunting.” Visual sightings of apparitions are a different phenomenon entirely, and infrasound research does not touch them.
Some earlier studies found infrasound linked to fatigue, nausea, and anxiety; others reported no significant effects at all. The inconsistencies were largely attributed to weak experimental controls, unverified sound exposures, and over-reliance on self-report. The new MacEwan study addressed those gaps by pairing verified infrasound delivery with both psychological and biological measurement, and by confirming that what participants believed about their exposure had no bearing on their cortisol response. That last piece is the methodological backbone of the whole thing.
The study was small and short-term, so the results need replication, but researchers say the findings warrant serious attention given how common infrasound sources are in everyday environments. Thirty-six people in a controlled lab setting is a first step, not a final answer. But it is a well-designed first step, and the biological measure of cortisol in saliva gives it more weight than a study relying purely on “did you feel scared, circle yes or no.”
The broader question the study leaves open is hard to ignore. If a brief lab exposure can nudge cortisol upward and darken mood in a measurable direction, what might hours of undetected infrasound do in offices, old apartments, or buildings long rumored to be haunted? Nobody has measured the infrasound levels in the old Victorian on the hill yet. That would be a next step worth funding.
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What the Pipes Already Knew
There is something oddly comforting and oddly unsettling in equal measure about all of this. Comforting because the creeping dread in an old building is not a sign of mental fragility or an overactive imagination; it is your body doing exactly what evolution built it to do, detecting a frequency your conscious mind cannot access and flagging it as potentially important. You are not being dramatic. You are being a mammal.
Unsettling because it means the feeling is real even when nothing is there. The cortisol is real. The irritability is real. The sense of unease is real. And none of it requires a ghost to produce it, just a building old enough to have a boiler that hums at the wrong frequency and pipes that groan when the pressure drops. Which describes a significant portion of the houses people live in, the offices people spend forty hours a week in, and the basements where laundry sits, unfolded, for longer than anyone will admit.
What the research does not do is make the experience smaller. There is a reason certain places have always felt different, the old church at the edge of town, the industrial building converted into lofts, the house with the strange history and the inexplicable chill in the back hallway. Something is happening in those places. The fact that it is a sound wave below 20 Hz rather than a restless spirit does not make the body’s response any less real, or the experience any less worth paying attention to. The body was right that something was there. It just had to tell the story it knew.
AI Disclaimer: This article was created with the assistance of AI tools and reviewed by a human editor.