A chamber study of respiratory and autonomic responses to hydrotreated vegetable oil exhaust using ECG-derived respiration

Background Air pollution is a major public health concern, contributing to cardiovascular and respiratory diseases. One of the main pathways by which air pollution affects cardiovascular health is through dysregulation of the autonomic nervous system (ANS), which impairs cardiac control. Hydrotreated vegetable oil (HVO) is a renewable fuel with unknown toxicity in comparison to conventional diesel, and the effects of HVO exhaust on autonomic and respiratory regulation remain unclear. Objective This study investigates the physiological responses to HVO exhaust exposure by assessing heart rate variability (HRV), ECG-derived respiration (EDR) and cardiorespiratory coupling (CRC). Methods A controlled exposure study was conducted with 19 healthy volunteers (10 males, 9 females, aged 20–55) who underwent four different exposure scenarios in a randomized, double-blind design: filtered air, filtered air with NaCl particles, HVO exhaust with an aftertreatment system, and HVO exhaust without aftertreatment. ECG signals were continuously recorded, and HRV, EDR, and CRC features were extracted. A linear mixed model was used to assess time- and exposure-dependent changes. Results No statistically significant differences in HRV, EDR, or CRC features were found between exposure scenarios. Conclusion In this study, short-term exposure to HVO exhaust, corresponding to EU OELs for one workday, was not associated with statistically significant changes in the ECG-derived autonomic, respiratory, or cardiorespiratory-coupling markers assessed in healthy volunteers at the studied pollutant concentrations.