Hear comes trouble.
Ghosts in the attic or goblins in the basement are not responsible for paranormal activity, claims an April 2026 study, which blames a home’s old pipes for those things that go bump in the night.
It’s just the rickety plumbing that’s humming.
“Consider visiting a supposedly haunted building — your mood shifts, you feel agitated, but you can’t see or hear anything unusual,” said Rodney Schmaltz, senior study author and psychology professor at Canada’s MacEwan University, in a statement.
“In an old building, there is a good chance that infrasound is present, particularly in basements where aging pipes and ventilation systems produce low-frequency vibrations,” he explained. “If you were told the building was haunted, you might attribute that agitation to something supernatural.
“In reality, you may simply have been exposed to infrasound.”
It’s an inaudible annoyance that triggers our internal alarms.
Infrasound is very low-frequency sound, below 20 hertz, which humans typically can’t hear, said the researchers. Despite it being undetectable to the ear, our bodies respond to the nuisance, which causes increased irritability and higher cortisol levels, per the report.
“Infrasound is pervasive in everyday environments, appearing near ventilation systems, traffic and industrial machinery,” Schmaltz said.
In the wild, some animals use it to communicate, while others avoid it altogether.
Humans, however, are often “exposed to it without knowing it,” according to the insider.
Schmaltz, along with his investigative team, recruited 36 participants to sit alone in a room while either calming or unsettling music played.
For half the participants, hidden subwoofers played infrasound at 18 hertz.
After listening, participants were asked to report their feelings, their emotional rating of the music and whether they thought the infrasound was present. They also gave saliva samples before and after listening.
The analysts found that respondents’ salivary cortisol levels were higher if they had been listening to infrasound. Folks from the subset also reported feeling more irritable and less interested and thinking the music was sadder.
But they couldn’t tell they were listening to infrasound.
“This study suggests that the body can respond to infrasound even when we can’t consciously hear it,” said Schmaltz. “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.”
Kale Scatterty, first author and Ph.D. student at the University of Alberta, confirmed the findings.
“Increased irritability and higher cortisol are naturally related, because when people feel more irritated or stressed, cortisol tends to rise as part of the body’s normal stress response,” Scatterty said. “But infrasound exposure had effects on both outcomes that went beyond that natural relationship.”
And while it’s certain that humans can sense but not identify infrasound, it is unclear whether prolonged exposure to the noise can impact health through consistently elevated cortisol levels and well-being issues related to lowered mood and increased irritability.
“Increased cortisol levels help the body respond to immediate stressors by inducing a state of vigilance,” said Trevor Hamilton, a psychology professor at MacEwan University and a corresponding author. “This is an evolutionarily adapted response that helps us in many situations.”
“However, prolonged cortisol release is not a good thing,” he warned. “It can lead to a variety of physiological conditions and alter mental health.”
The monumental implications of their data notwithstanding, the specialists concede that further probing is needed to fully understand how infrasound influences human emotion and behavior.
“This study was in many ways a first step towards understanding the effects of infrasound on humans,” Scatterty said. “So far, we’ve only tested a specific frequency. There could be many more frequencies and combinations that have their own differential effects.”
Schmaltz hopes that additional inquiries into how certain frequencies and combinations affect mood and physiology will help to inform noise regulations and building design standards.
“As someone who studies pseudoscience and misinformation, what stands out to me is that infrasound produces real, measurable reactions without any visible or audible source,” he said.
“So, the next time something feels inexplicably off in a basement or old building, consider that the cause might be vibrating pipes rather than restless spirits.”
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