Full Breakdown
Low-Frequency Infrasound Triggers Irritability and Cortisol Rise in Lab Study
5/9/2026, 11:41:47 AM
Infrasound Exposure Alters Mood and Hormone Levels
Thirty-six adult participants listened to music while a concealed 18-Hz tone (75–78 dB) played beneath it for a brief period. Half heard the tone; half heard music alone. Those exposed reported higher irritability, reduced engagement, and judged the music as sadder. Salivary cortisol rose in the infrasound group, yet participants could not reliably identify the hidden vibration.
Infrasound: Sources and Mechanisms
Infrasound denotes sound below 20 Hz, typically inaudible to humans. Natural events such as storms and volcanic activity generate it, while human sources include ventilation fans, elevator motors, pumps, traffic and industrial machinery. Because low-frequency waves travel far and bypass barriers, they can accumulate in basements and older buildings where aging pipes and ventilation systems operate.
Implications for Buildings and Perceived Hauntings
The results offer a physiological basis for the uneasy feeling often reported in old or poorly ventilated spaces. By linking inaudible vibration to mood and cortisol, the study suggests that design or maintenance—especially around fans, pumps, and long pipe runs—could reduce unwanted emotional effects. The evidence also counters supernatural explanations for “haunted” basements.
Official Statements & Responses
The work, published in Frontiers in Behavioral Neuroscience, notes that the body can react to inaudible infrasound and that the cortisol rise signals immediate stress. The authors stress the need for broader testing of frequencies, exposure lengths, and real-world settings before informing building codes or noise-regulation standards. The modest sample size prompts larger investigations.
Criticism & Limitations
The trial involved a small, demographically narrow sample—predominantly young women—and examined only a single clean tone. Laboratory conditions differ from mixed-frequency environments of actual buildings, so larger, more diverse studies are needed to assess long-term health impacts and identify disruptive frequency combinations.
Verbatim Quotes
- “This study suggests that the body can respond to infrasound even when we can’t consciously hear it,” — Rodney M. Schmaltz, Ph.D., MacEwan University
- “Increased cortisol levels help the body respond to immediate stressors by inducing a state of vigilance,” — Trevor J. Hamilton, Ph.D., MacEwan University
- “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.” — Rodney M. Schmaltz, Ph.D., MacEwan University
- “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,” — Kale Scatterty, Ph.D. candidate, University of Alberta
What's Next
The team plans to test a broader frequency range and longer exposure periods in real-world settings such as occupied basements and older offices. Findings could shape future noise-regulation standards and help engineers locate and mitigate low-frequency sources.
