Overview
- Researchers reported that exposing 36 volunteers to about 18 hertz infrasound made them more irritable and less engaged and led them to rate music as sadder, with cortisol remaining elevated after the session.
- The team mixed a barely audible 18 hertz tone, delivered by hidden subwoofers, into calming or unsettling music and took saliva samples before and after to track cortisol.
- Participants could not tell when the infrasound was playing, yet both mood ratings and stress hormones shifted in a negative direction.
- The authors say low rumbles from pipes, ventilation, traffic, heaters, turbines, or storms could trigger eerie sensations people sometimes label as hauntings.
- They caution that the lab test was brief with a small, mostly female sample at a single tone and urge larger real-world studies and efforts to identify and reduce infrasound pollution.