title: Higher fine particulate matter and temperature levels impair exercise capacity in cardiac patients.
abstract: OBJECTIVE
  Fine particulate matter (PM2.5) air pollution and variations in ambient temperature have been linked to increased cardiovascular morbidity and mortality. However, no large-scale study has assessed their effects on directly measured aerobic functional capacity among high-risk patients.
  
  
  METHODS
  Using a cross-sectional observational design, we evaluated the effects of ambient PM2.5 and temperature levels over 7 days on cardiopulmonary exercise test results performed among 2078 patients enrolling into a cardiac rehabilitation programme at the University of Michigan (from January 2003 to August 2011) using multiple linear regression analyses (controlling for age, sex, body mass index).
  
  
  RESULTS
  Peak exercise oxygen consumption was significantly decreased by approximately 14.9% per 10 μg/m(3) increase in ambient PM2.5 levels (median 10.7 μg/m(3), IQR 10.1 μg/m(3)) (lag days 6-7). Elevations in PM2.5 were also related to decreases in ventilatory threshold (lag days 5-7) and peak heart rate (lag days 2-3) and increases in peak systolic blood pressure (lag days 4-5). A 10°C increase in temperature (median 10.5°C, IQR 17.5°C) was associated with reductions in peak exercise oxygen consumption (20.6-27.3%) and ventilatory threshold (22.9-29.2%) during all 7 lag days. In models including both factors, the outcome associations with PM2.5 were attenuated whereas the effects of temperature remained significant.
  
  
  CONCLUSIONS
  Short-term elevations in ambient PM2.5, even at low concentrations within current air quality standards, and/or higher temperatures were associated with detrimental changes in aerobic exercise capacity, which can be linked to a worse quality of life and cardiovascular prognosis among cardiac rehabilitation patients.
authors.affiliation: Department of Life, Health and Environmental Sciences, Division of Internal Medicine and Nephrology, University of L'Aquila, L'Aquila, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Giorgini
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Melvyn
authors.initials: M
authors.lastname: Rubenfire
authors.affiliation: Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Ritabrata
authors.initials: R
authors.lastname: Das
authors.affiliation: Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Theresa
authors.initials: T
authors.lastname: Gracik
authors.affiliation: Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Environmental Health Sciences, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Masako
authors.initials: M
authors.lastname: Morishita
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Bard
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Jackson
authors.affiliation: Air Quality Division, Department of Environmental Quality, Lansing, Michigan, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Fitzner
authors.affiliation: Department of Life, Health and Environmental Sciences, Division of Internal Medicine and Nephrology, University of L'Aquila, L'Aquila, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ferri
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Brook
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D000072038:Cardiac Rehabilitation; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000009:adverse effects / Q000032:analysis / Q000517:prevention & control; D005080:Exercise Test / Q000187:drug effects / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D007320:Inspiratory Capacity / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis; D005082:Physical Exertion / Q000187:drug effects*; D011379:Prognosis; D011788:Quality of Life; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter