Heart rate variability under acute stress and noise in healthy subjects:
A tool to study autonomic activity in tinnitus?
Abstract
Introduction: Individuals with hearing disorders such as tinnitus often
experience high levels of stress, anxiety, depression, and decreased
sound tolerance. These factors may be related to maladaptive autonomic
regulation, affecting their response to acute stress. Heart rate
variability (HRV) is a reliable measure of autonomic activity, but its
interaction with psychological factors is not well understood.
Objectives: The aim was to develop a multimodal stress induction
protocol in a non-clinical population and to determine how psychological
factors influence physiological responses. Methods: Electrocardiograms
were recorded from 30 healthy young adults during three stress tasks:
mental arithmetic, noise exposure, and a cold pressor test. Heart rate
(HR) and root mean square of successive differences (RMSSD) were used to
index autonomic activity. Participants also completed questionnaires on
perceived stress, noise sensitivity, anxiety, and depression to examine
relationships with HRV. Results: All tasks produced significant
time-dependent effects on HRV features, but to different extents. Mental
arithmetic produced the largest increase in HR and decrease in RMSSD. In
contrast, the noise task showed a significant decrease in HR without a
change in RMSSD, suggesting that the task induced relaxation. In the
CPT, females showed increased HR but a decrease in RMSSD, whereas males
showed the reverse pattern. Psychological factors significantly
interacted with HRV dynamic changes during mental and noise tasks, but
not during CPT. Conclusions: HRV responses to acute stress are
non-stationary and influenced by psychological factors. Thus, this
protocol presents an original approach to study autonomic activity in
stress-related conditions such as tinnitus.