Air pollution compromises exercise responses more in healthy people than ex-smokers
31 Oct 2021
Exposure to traffic-related air pollution (TRAP) takes a toll on exercise responses among healthy people but not former smokers with or without chronic obstructive pulmonary disorder (COPD), a study has found.
Researchers examined the adverse effect of pre-exercise exposure to TRAP (diesel exhaust [DE]300: fine particulate matter [PM2.5] 300 μg/m3) on exercise endurance, exertional dyspnoea, and cardiorespiratory responses to exercise, and whether the magnitude of effect was greater in participants with mild-to-moderate COPD (n=9) vs former smokers with normal spirometry (n=9) and healthy never-smokers (controls, n=11).
In this double-blind, randomized, crossover study, the participants were separately exposed to filtered air (FA) and DE300 for 2 hours separated by a minimum of 4 weeks. Following 2.5 hours of exposure, the participants performed symptom limited constant load cycling tests with detailed cardiorespiratory and exertional symptom measurements.
Results showed that TRAP had a substantial negative effect on exercise endurance time in healthy controls (DE300 vs FA: 10.2 vs 12.9 min, respectively; p=0.03) but not in ex-smokers without COPD (10.1 vs 12.2 min; respectively; p=0.57) or ex-smokers with COPD (9.8 vs 8.4 min, respectively; p=0.31).
Moreover, there were marked elevations in inspiratory duty cycle and absolute end-expiratory and end-inspiratory lung volumes, with dyspnoea ratings being high at select submaximal measurement times, only in healthy controls.