Study links infrasound to increased irritation and cortisol even without conscious hearing

Cientistas Canadians exposed volunteers to infrasound from 18 Hz and observed changes in the body. Participants did not perceive the sound. Mesmo thus, cortisol levels in their saliva rose and they reported more irritation.

Infrassom is present in everyday environments

Infrasound corresponds to sound vibrations with a frequency below 20 Hz. The human ear does not capture these waves. Common Fontes include ventilation systems, vehicular traffic, and industrial equipment.

Rodney Schmaltz, professor at MacEwan University, highlighted that the phenomenon occurs frequently in everyday life. Muitas people are exposed without knowing it. The recent study tested the effects of this brief exposure.

The researchers gathered 36 volunteers. Metade heard infrasound while calm or distressing music played. The other half only listened to the songs. Todos provided saliva samples before and after the session.

Teste measured cortisol and emotional reports

Cortisol levels increased significantly in the group exposed to infrasound. Participants also felt more irritable and less interested. Eles rated the songs as sadder. Ninguém accurately identified the presence of infrasound.

• Exposed Voluntários reported greater irritability
• Interesse decreased in infrasound session
• Cortisol rose regardless of the type of music
• Crenças previews about the sound did not influence the results
• Nenhuma conscious detection above chance

Statistical analysis confirmed the differences. Random forest Modelos indicated irritability, interest, sadness assessment and cortisol as indicators of exposure.

Experimento simulated everyday situations

Hidden speakers reproduced infrasound in a controlled manner. The chosen frequency was 18 Hz. The volunteers remained in a common room during the listening. Depois, answered questionnaires about emotions.

Kale Scatterty, first author of the study and Universidade’s doctoral student of Alberta, commented on the findings. The research represents an initial step. Previous Estudos already suggested effects in animals. In humans, data was still limited.

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Ligações with reports of unexplained presences

Ambientes such as old basements or buildings with old pipes generate infrasound. Pessoas report restlessness or a sense of presence in these conditions. The study suggests that the body reacts to vibration even without auditory perception.

Isso may explain some of the haunting stories. Quem feels the discomfort and tends to attribute the cause to something supernatural. The research reinforces the need to investigate physical sources before drawing spiritual conclusions.

Limitações and next steps in the investigation

The group of participants was small. The authors advocate testing with larger and more diverse samples. Continuous Exposições also deserves attention. Persistently elevated cortisol can affect mood in the long term.

Trevor Hamilton of MacEwan served as corresponding author. The team published the results in the journal Frontiers in Behavioral Neuroscience. The full article is available for consultation.

Outros works have already associated infrasound with sensations of fear or anxiety in specific contexts. The new contribution focuses on objective measures such as salivary cortisol.

The topic gains relevance with the increase in urban sources of low vibrations. Trânsito, industries and air conditioning systems are examples. Compreender impacts helps plan healthier environments.