Full Breakdown
Infrasound Exposure Triggers Stress Hormone Release and Mood Shifts, Offering a Scientific Lens on Haunted Sensations
4/29/2026, 2:55:24 AM
Infrasound Linked to Elevated Cortisol and Mood Changes
A study published in *Frontiers in Behavioral Neuroscience* examined how inaudible low-frequency sound (infrasound < 20 Hz) influences human physiology and affect. Thirty-six participants listened to calming or unsettling music while hidden sub-woofer speakers emitted an 18 Hz tone in half of the sessions. Saliva samples taken before and after exposure showed a statistically significant rise in cortisol (p = 0.022, r_rb = 0.390). Participants also reported higher irritability (p = 0.049), greater sadness appraisal of the music (p = 0.002), and reduced interest, despite being unable to detect the tone (detection at chance, p = 0.241).
Background: Low-Frequency Sound and Prior Paranormal Research
Infrasound, produced by thunderstorms, traffic, ventilation systems, and industrial machinery, is normally imperceptible to human hearing. Earlier investigations, such as Vic Tandy’s 1980s observation that disabling a fan eliminated “haunted” visual phenomena, and Richard Wiseman’s early-2000s field studies of reputedly haunted sites, suggested environmental factors—including magnetic fields, humidity, and low-frequency vibrations—could underlie eerie sensations.
Key Researchers and Institutions
- Rodney Schmaltz, psychologist, MacEwan University (senior author)
- Kale Scatterty, PhD student, University of Alberta (first author)
- Trevor Hamilton, professor, MacEwan University (corresponding author)
- Vic Tandy, British engineer (historical case)
- Richard Wiseman, University of Hertfordshire (paranormal perception research)
Experimental Design and Quantitative Findings
The 2 × 2 between-subjects design crossed music valence (calming vs. unsettling) with infrasound presence (on vs. off). Salivary cortisol increased in the infrasound condition regardless of music type. Self-report scales indicated that participants rated the music as sadder and felt more irritable, yet their confidence in detecting the tone did not differ from chance. Random-forest modeling identified cortisol, irritability, sadness appraisal, and disinterest as key predictors of exposure.
Official Statements & Institutional Responses
Schmaltz emphasized that the body can react to vibrations without conscious auditory perception and noted the prevalence of infrasound in basements and aging infrastructure. Scatterty highlighted that the cortisol rise exceeded what would be expected from irritability alone, suggesting a direct physiological effect. Hamilton described the cortisol surge as an evolutionarily adaptive vigilance response, warning that chronic activation could contribute to health issues.
Criticism, Limitations, and Divergent Findings
The authors acknowledge several constraints: a modest sample (n = 36), a single frequency (18 Hz), limited demographic diversity, and reliance on post-exposure self-reports rather than continuous behavioral measures. Prior studies have reported mixed outcomes, and the present work did not observe anxiety effects, contrasting with animal literature linking infrasound to anxiety.
Conflicting Reports & Knowledge Gaps
While the current data support a link between infrasound and stress markers, earlier field work (Wiseman) identified additional environmental variables (magnetic fields, humidity) that may co-occur with low-frequency sound. The study also does not substantiate claims that infrasound caused the “Havana Syndrome,” a point the researchers deem unlikely given the required sound intensity. Long-term health consequences of chronic low-level exposure remain unquantified.
Verbatim Quotes
- “Consider visiting a supposedly haunted building. Your mood shifts, you feel agitated, but you can’t see or hear anything unusual. 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. 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.” — Rodney Schmaltz, Psychologist, MacEwan University
- “This study suggests that the body can respond to infrasound even when we can’t consciously hear it,” — Rodney Schmaltz
- “Increased cortisol levels help the body respond to immediate stressors by inducing a state of vigilance,” — Trevor Hamilton, Professor, 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 Schmaltz
- “Discussion: Without auditory detection nor expectancy effects, infrasound exposure was linked to elevated cortisol and more negative affective self-reporting.” — *Frontiers in Behavioral Neuroscience* discussion
Future Directions and Potential Policy Implications
Researchers plan to test multiple frequencies, longer exposure periods, and real-world environments such as historic buildings and urban traffic corridors. Findings could inform building-design standards, ventilation system maintenance, and noise-regulation policies aimed at mitigating inadvertent infrasound exposure and its associated stress responses.
