Enhancing the regulatory function of the autonomic nervous system using sounds with inaudible high-frequency components

The dysregulation of the autonomic nervous system (ANS) activity notably contributes to the onset and progression of numerous diseases, including lifestyle-related and psychiatric disorders. This necessitates the development of effective nonpharmacological methods for regulating ANS function for therapeutic purposes and disease prevention. This study examined how the presence or absence of the inaudible high-frequency component (HFC) of sounds—which activates deep-brain structures—affects the ANS regulatory function. Under the N-back task condition, which requires concentration, exposure to sounds with HFC resulted in significantly higher sympathetic and parasympathetic nervous activities compared to sounds without HFC. Conversely, under the relaxation condition, the sounds with HFC significantly suppressed sympathetic nervous activity relative to sounds without HFC. Therefore, unlike pharmacological agents, which typically exert unidirectional effects on the ANS activity, sounds with HFC may flexibly adjust the sympathetic and parasympathetic nervous activities in response to situational demands.