Monitoring the short-term biological response of environmental noise in real-life sleep conditions

A protocol is developed to measure the short-term biological response to environmental noise during sleep. It is designed as potential component in the Human Biomonitoring Program of the Flemish Government. The focus of the protocol is the user-friendliness and the use of non-invasive but accurate technology. The sensor boxes are deployed without third party support using a simple set of instructions. The setup includes simultaneous indoor and outdoor spectral noise monitoring to discriminate between indoor and outdoor disturbances. Actimetry and heart rate are monitored on-torso to detect potential arousals and awakenings. The data analysis is performed in a 10 second resolution and is based on the heart rate variability (HRV) of nine teenage subjects. The bedroom insulation is included using the difference between outdoor and indoor noise. The relevant biomarker is the HF/LF ratio, a HRV parameter related to the activation of the autonomous nervous system, shows significant correlation with the environmental noise. Peak emergence and augmented background noise also result in enhanced activation of the autonomous nervous system. This novel approach delivers an objective measure of the short-term biological effect of noise during sleep in real-life conditions. The affordability and low-invasive design allow large-scale deployment in future health studies.