Recent research has unveiled an intriguing connection between infrasound and our emotional responses, particularly in environments like old buildings. While people may not consciously perceive infrasound, the body reacts to it, leading to increased irritability and elevated cortisol levels, a hormone associated with stress.
Prof. Rodney Schmaltz from MacEwan University, the lead author of a study published in Frontiers in Behavioral Neuroscience, explains, "Infrasound is commonly found in everyday settings such as near ventilation systems, heavy traffic, and industrial equipment. Many individuals are unknowingly exposed to it. Our research indicates that even short bursts of infrasound can influence mood and increase cortisol levels, underscoring the need to explore its impacts in real-world scenarios."
Consider a visit to an old, reputedly haunted building. You might notice a shift in your mood or feel a sense of agitation, even without any visible or audible disturbances. In such settings, particularly in basements where aging infrastructure can generate low-frequency vibrations, infrasound may be at play. If you associate this discomfort with supernatural occurrences, you might be overlooking the physical source--namely, infrasound.
Investigating Infrasound's Impact on Mood and Stress
To delve deeper into this phenomenon, researchers conducted an experiment involving 36 participants. They were placed individually in a room and exposed to either soothing or unsettling music. For half of the group, hidden subwoofers emitted infrasound at a frequency of 18 Hz.
Post-experiment, participants provided feedback on their emotional state, rated the music's tone, and indicated their beliefs about infrasound presence. Saliva samples were also collected to measure cortisol levels before and after the listening sessions.
Infrasound's Connection to Cortisol and Irritability
The findings revealed significant physiological and emotional shifts. Those exposed to infrasound exhibited increased salivary cortisol and reported heightened irritability, diminished engagement, and a tendency to perceive the music as more melancholic. Despite these changes, participants could not reliably determine whether infrasound was present.
"Our study suggests the body can respond to infrasound even when it's not consciously detected," noted Schmaltz. "Participants couldn't accurately identify infrasound exposure, and their beliefs about its presence did not influence their cortisol levels or mood." According to Kale Scatterty, the study's lead author and PhD student at the University of Alberta, "Increased irritability and cortisol levels are interconnected; however, the effects of infrasound extended beyond this natural correlation."
Understanding the Unheard: Infrasound's Hidden Effects
The research highlights that while humans may not consciously perceive infrasound, the body registers its presence in some capacity. The precise biological mechanisms remain unclear, and researchers caution that prolonged exposure could potentially affect health by maintaining elevated cortisol levels and contributing to persistent irritability.
Prof. Trevor Hamilton, a co-author of the study, emphasized, "While elevated cortisol can help the body respond to immediate stressors, chronic elevation is detrimental, leading to various health issues." The study serves as a foundational step in understanding how infrasound influences human emotions and behaviors, with future research needed to explore a broader range of frequencies and their effects.
As researchers continue to investigate this phenomenon, the implications for building design and noise regulations could be profound. In recognizing the tangible effects of infrasound, we may pave the way for healthier environments that enhance well-being and comfort.