Heart Rate Variability and Particulate Exposure in Vehicle Maintenance Workers: A Pilot Study

Abstract

The association between occupational exposure to PM_2.5 and heart rate variability was investigated in a repeated measures, longitudinal study of vehicle maintenance workers occupationally exposed to automobile emissions. Five subjects were monitored for occupational exposure to fine particulate matter (PM_2.5) on 6 workdays using an aerosol photometer, validated with side-by-side sampling with a gravimetric method. End-of-day heart rate variability statistics were derived using short-term electrocardiogram recordings for each participant. Workplace carbon monoxide and outdoor, ambient fine particulate matter were also monitored. Regression statistics were used to investigate associations between same-day PM_2.5 levels and heart rate variability statistics using mixed-effects multiple regression of pooled data. No statistically significant associations were observed between occupational PM_2.5 and measures of heart rate variability. A statistically significant increase in total spectral power was associated with ambient PM_2.5 (p < 0.05). The data suggest a threshold below which no degradation in cardiac autonomic control of healthy workers occurs when challenged by occupational PM_2.5 exposure. This study was limited in population, exposure level, and type of particulate exposures. Additional studies are recommended on broader occupational populations.

Keywords:

• heart rate variability
• particulate matter
• PM_2.5

ACKNOWLEDGMENT

This research was supported by NIOSH ERC Pilot Project Research Training Program Grant No. T42/CCT510420 through the University of Cincinnati Education and Research Center.

Notes

^A Originally provided incorrect medication name; excluded in later statistical analysis.

^A Heart rate was averaged over the 5-min ECG reading.