Effect of simultaneous physical and auditory stressors on cardiorespiratory response

In occupational medicine, monitoring individual stress-related physiological responses is an effective tool for minimizing health risks at the workplace. From an audiology perspective, this particularly concerns the effects of auditory stress, which leads to increased listening effort with subsequent hearing fatigue. A study was conducted to investigate whether cardio-respiratory responses can detect the effects of a multi-level combination of physical and auditory stressors. To investigate their measurability and determine whether an interaction exists, a selection of cardio-respiratory vital parameters such as heart rate, features in the time and frequency domain of the heart rate variability, breathing rate, respiratory minute volume, and the respiratory quotient were analyzed. The results showed a significant main effect of physical stress on all assessed parameters. Auditory stress demonstrated a significant impact on breathing frequency, root mean square of successive differences of interbeat intervals, and the power components of the low and high frequency bands of the heart rate variability. No interaction between auditory and physical stressors was observed across any of the examined parameters. From these results we conclude that physiological responses to different sources of stress can be recorded within selected vital parameters, independent of external stimuli such as ambient noise. In an occupational context, we see potential in tracking individual auditory stress by monitoring cardio-respiratory parameters, especially breathing patterns. By knowing the individual (auditory) stress level, conclusions could be drawn about the worker's ability to concentrate and further measures could be taken to combat safety risks in the work environment.