Personal exposure to specific volatile organic compounds and acute changes in lung function and heart rate variability among urban cyclists

Few studies have examined the acute cardiorespiratory effects of specific volatile organic compound (VOC) exposures from traffic pollution. A cross-over study was conducted among 42 healthy adults during summer 2010 in Ottawa, Canada. Participants cycled for 1-h along high and low-traffic routes and VOC exposures were determined along each route. Lung function, exhaled nitric oxide, and heart rate variability were monitored before cycling and 1–4h after the start of cycling. Bayesian hierarchical models were used to examine the relationship between 26 VOCs and acute changes in clinical outcomes adjusted for potential confounding factors. Each inter-quartile range (IQR) increase in propane/butane exposure was associated with a 2.0millisecond (ms) (95% CI: 0.65, 3.2) increase in SDNN (standard deviation of normal-to-normal intervals), a 24ms2 (95% CI: 6.6, 41) increase in HF (high frequency power), and a 65ms2 (95% CI: 11, 118) increase in LF (low frequency power) in the hours following cycling. IQR increases in ethane and isoprene were associated with a 5.8ms (95% CI: −9.8, −1.7): decrease in SDNN and a 24ms2 (95% CI: −44, −7.9) decrease in HF, respectively. IQR increases in benzene exposure were associated with a 1.7ppb (95% CI: 1.1, 2.3) increase in exhaled nitric oxide and each IQR increase in 3-methylhexane exposure was associated with a 102mL (95% CI: −157, −47) decrease in forced expiratory volume in 1-s. Exposure to traffic-related VOCs may contribute to acute changes in lung function, inflammation, or heart rate variability. ► The acute cardiorespiratory effects of VOC exposures were examined among cyclists. ► Outcomes included heart rate variability, lung function, and exhaled NO. ► Most VOCs were not associated with cardiorespiratory outcomes. ► Heterogeneous associations were observed for a small number of VOCs. ► Future studies should replicate these findings.