This study aims to evaluate the effectiveness of pure tone auditory stimulation on stress relief by comparing subjective and physiological indices. Participants were exposed to various single-frequency sounds (80 Hz to 2500 Hz) while performing a mentally demanding arithmetic task designed to induce stress. We measured changes in subjective stress levels (via questionnaires), heart rate (via pulse wave analysis), and brain activity (via NIRS). The results revealed that certain high-frequency stimuli, particularly 1500 Hz and 2500 Hz, were associated with increased subjective stress and prefrontal cortex activation, suggesting a possible stress-inducing effect. These findings imply that auditory stimuli do not always lead to relaxation and that frequency, context, and individual sensitivity must be considered in designing effective sound environments for stress management.
Okazaki et al. (Wed,) studied this question.