Low frequency noise enhances cortisol among noise sensitive subjects during work performance

Area of Science:

• Environmental Health
• Occupational Health
• Psychoneuroendocrinology

Background:

• Workplace noise, particularly low-frequency noise, is a common environmental stressor.
• Individual sensitivity to noise varies, potentially influencing physiological responses.
• The impact of moderate noise levels on neuroendocrine function requires further investigation.

Purpose of the Study:

• To investigate the physiological stress responses to low-frequency noise compared to reference noise.
• To examine the role of noise sensitivity in modulating stress responses during work tasks.
• To assess the effect of noise exposure on salivary free cortisol concentrations and perceived stress.

Main Methods:

• 32 subjects performed tasks for 2 hours under two noise conditions (low-frequency vs. reference spectrum) at 40 dBA.
• Salivary free cortisol, stress, and annoyance were measured before, during, and after noise exposure.
• Subjects were categorized as high- or low-sensitive to noise based on questionnaires.

Main Results:

• Low-frequency noise was rated as more annoying and disruptive than reference noise.
• Cortisol concentrations were not significantly modulated by noise or noise sensitivity alone.
• The normal circadian decline in cortisol was significantly attenuated in high-noise-sensitive subjects exposed to low-frequency noise.

Conclusions:

• Physiological evidence of increased stress in noise-sensitive individuals exposed to low-frequency noise during work was demonstrated.
• Moderate levels of noise, especially low-frequency noise, can affect neuroendocrine activity.
• Long-term effects of workplace noise exposure warrant further research.