Emerging scientific inquiry suggests that infrasound, characterized by sound waves below the audible threshold of 20 Hz, can precipitate elevated cortisol concentrations and heightened irritability, thereby providing a potential scientific rationale for the unsettling ambiance often associated with certain reputedly haunted locations.
The investigational work by Scatterty and colleagues employed a dual approach, integrating subjective self-assessments with objective physiological metrics to substantiate the irritant and aversive qualities of infrasound in human subjects. Concurrently, infrasound appears to correlate with an amplification of adverse emotional responses.
The acoustic definition of infrasound delineates it as sound originating from frequencies that do not exceed 20 Hz.
This phenomenon can manifest naturally, being generated, for instance, through geological processes such as seismic or volcanic activity, meteorological events like convective storms, and interactions between air and water, as observed in situations involving upstream water displacement.
Conversely, infrasound is also a pervasive element in developed urban environments, frequently emanating from sources such as ventilation systems, air conditioning units, resonating pipes, vehicular traffic, and building infrastructure including power, heating, and mechanical systems.
Moreover, preliminary field recordings have documented the presence of low-frequency acoustic energy within the infrasound spectrum originating from analogous urban sources, as well as during live musical performances.
“Infrasound is ubiquitous in our daily surroundings, manifesting in proximity to ventilation apparatus, transportation networks, and industrial machinery,” stated Professor Rodney Schmaltz of MacEwan University.
“A significant portion of the populace encounters it without their conscious awareness. Our findings indicate that even brief exposure can induce mood alterations and elevate cortisol levels, underscoring the imperative of comprehending infrasound’s impact on individuals within real-world contexts.”
For the purpose of their investigation, the researchers enlisted the participation of 36 individuals, inviting them to occupy a solitary room while being exposed to either soothing or disquieting musical compositions.
In half of the participant cohort, imperceptible subwoofers emitted infrasound at a frequency of 18 Hz. Following the listening period, participants were prompted to articulate their subjective feelings, provide an emotional rating of the music, and indicate whether they perceived the presence of infrasound. Furthermore, they submitted saliva samples both prior to and subsequent to the auditory stimulus.
The empirical data revealed a measurable increase in participants’ salivary cortisol concentrations following exposure to infrasound.
These individuals also reported experiencing heightened irritability, diminished engagement, and a perception of the music as more melancholic. Notably, they remained unaware of the infrasound’s presence.
“This investigation suggests that physiological responses to infrasound can occur even when we are unable to consciously detect it,” articulated Professor Schmaltz.
“Participants were consistently unable to accurately discern whether infrasound was being emitted, and their preconceptions regarding its presence exerted no discernible influence on their cortisol levels or emotional state.”
“The elevation of irritability and cortisol levels are intrinsically linked, as heightened feelings of irritation or stress typically trigger an increase in cortisol as a compensatory mechanism within the body’s standard stress response,” explained Kale Scatterty, a doctoral candidate at the University of Alberta.
“However, the infrasound exposure demonstrated effects on both of these indicators that extended beyond this inherent association.”
These outcomes suggest that humans possess the capacity to perceive infrasound without necessarily identifying its specific source, although the underlying physiological pathway remains a subject of ongoing investigation.
Furthermore, they imply a necessity to examine the potential health implications of protracted infrasound exposure, particularly concerning consistently elevated cortisol levels and attendant well-being issues stemming from diminished mood and increased irritability.
“Elevated cortisol levels serve to augment the body’s capacity to confront immediate stressors by fostering a state of heightened awareness,” stated Professor Trevor Hamilton of MacEwan University.
“This represents an evolutionarily advantageous response that proves beneficial in a multitude of scenarios. Nevertheless, sustained cortisol secretion is detrimental. It can precipitate a range of physiological disorders and negatively impact mental health.”
The published findings are featured in the scholarly publication Frontiers in Behavioral Neuroscience.
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Kale R. Scatterty et al. 2026. Infrasound exposure is linked to aversive responding, negative appraisal, and elevated salivary cortisol in humans. Front. Behav. Neurosci 20; doi: 10.3389/fnbeh.2026.1729876
