title: Controlled exposure to combined particles and ozone decreases heart rate variability.
abstract: 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.
authors.affiliation: Lung Biology Center, University of California, Northern California Center for Occupational and Environmental Health, San Francisco, Calif, USA. karronpower@comcast.net
authors.forename: Karron LeGarie
authors.initials: KL
authors.lastname: Power
authors.forename: John
authors.initials: J
authors.lastname: Balmes
authors.forename: Colin
authors.initials: C
authors.lastname: Solomon
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects*; D001249:Asthma; D002244:Carbon / Q000009:adverse effects*; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D005374:Filtration; D005541:Forced Expiratory Volume; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000009:adverse effects*; D010126:Ozone / Q000009:adverse effects*; D052638:Particulate Matter / Q000009:adverse effects*; D010865:Pilot Projects; D011795:Surveys and Questionnaires
chemical_list: D000393:Air Pollutants; D009566:Nitrates; D052638:Particulate Matter; D010126:Ozone; D002244:Carbon; C006568:ammonium nitrate