title: Reduced exercise tolerance and pulmonary capillary recruitment with remote secondhand smoke exposure.
abstract: BACKGROUND
  Flight attendants who worked on commercial aircraft before the smoking ban in flights (pre-ban FAs) were exposed to high levels of secondhand smoke (SHS). We previously showed never-smoking pre-ban FAs to have reduced diffusing capacity (Dco) at rest.
  
  
  METHODS
  To determine whether pre-ban FAs increase their Dco and pulmonary blood flow (Qc) during exercise, we administered a symptom-limited supine-posture progressively increasing cycle exercise test to determine the maximum work (watts) and oxygen uptake (VO2) achieved by FAs. After 30 min rest, we then measured Dco and Qc at 20, 40, 60, and 80 percent of maximum observed work.
  
  
  RESULTS
  The FAs with abnormal resting Dco achieved a lower level of maximum predicted work and VO2 compared to those with normal resting Dco (mean±SEM; 88.7±2.9 vs. 102.5±3.1%predicted VO2; p = 0.001). Exercise limitation was associated with the FAs' FEV(1) (r = 0.33; p = 0.003). The Dco increased less with exercise in those with abnormal resting Dco (mean±SEM: 1.36±0.16 vs. 1.90±0.16 ml/min/mmHg per 20% increase in predicted watts; p = 0.020), and amongst all FAs, the increase with exercise seemed to be incrementally lower in those with lower resting Dco. Exercise-induced increase in Qc was not different in the two groups. However, the FAs with abnormal resting Dco had less augmentation of their Dco with increase in Qc during exercise (mean±SEM: 0.93±0.06 vs. 1.47±0.09 ml/min/mmHg per L/min; p<0.0001). The Dco during exercise was inversely associated with years of exposure to SHS in those FAs with ≥10 years of pre-ban experience (r = -0.32; p = 0.032).
  
  
  CONCLUSIONS
  This cohort of never-smoking FAs with SHS exposure showed exercise limitation based on their resting Dco. Those with lower resting Dco had reduced pulmonary capillary recruitment. Exposure to SHS in the aircraft cabin seemed to be a predictor for lower Dco during exercise.
authors.affiliation: University of California San Francisco Flight Attendants Medical Research Institute Center of Excellence, San Francisco, California, United States of America. mehrdad.arjomandi@ucsf.edu
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Arjomandi
authors.forename: Thaddeus
authors.initials: T
authors.lastname: Haight
authors.forename: Nasrat
authors.initials: N
authors.lastname: Sadeghi
authors.forename: Rita
authors.initials: R
authors.lastname: Redberg
authors.forename: Warren M
authors.initials: WM
authors.lastname: Gold
mesh_terms: D000328:Adult; D000368:Aged; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D000401:Aircraft; D015331:Cohort Studies; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects* / Q000502:physiology; D005260:Female; D006801:Humans; D008168:Lung / Q000098:blood supply / Q000187:drug effects / Q000502:physiology; D008875:Middle Aged; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011652:Pulmonary Circulation / Q000187:drug effects* / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D000395:Air Pollutants, Occupational; D014028:Tobacco Smoke Pollution