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Updated: Jun 28, 2026

Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure
Published on: August 25, 2017
Controlled exposure to combined particles and ozone decreases heart rate variability
Karron LeGarie Power1, John Balmes, Colin Solomon
1Lung Biology Center, University of California, Northern California Center for Occupational and Environmental Health, San Francisco, Calif, USA. karronpower@comcast.net
Objective:
This experiment was designed to test if controlled exposure to particles and ozone would result in decreased heart rate variability (HRV).
Methods:
Five asthmatic adults were exposed for 4 hours to; filtered-air, carbon and ammonium nitrate particles, and particles and ozone. Twenty-minute electrocardiograms were obtained before and after each exposure.
Results:
Standard deviation of all normal-to-normal beat intervals (SDNN) decreased significantly across particles and ozone exposure compared with across filtered-air exposure (P = 0.01). Changes in SDNN-I (P = 0.04) and normalized low and high frequency (P = 0.02) were also seen across particles and ozone exposure; although these changes may best be characterized as trends given the small sample size. No significant changes in HRV were seen across the filtered-air or particles-only exposures.
Conclusions:
The results of this study suggest that combined particle and ozone exposure may decrease HRV in asthmatics. Further investigation is needed to confirm this finding.
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