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Harris, Owen Drake

University of British Columbia

Ground-level ozone (O₃) is a common airborne pollutant well recognized to impair pulmonary function and cause negative respiratory symptoms when inhaled. Due to a wide range of inter-individual variability in responses, a lack of consensus as to whether O₃ exposure limits exercise capability exists. Healthy, well-trained male (n=13) and female (n=7) endurance athletes were recruited to complete a double-blinded, randomized crossover study to address the research question. Participants were screened for inclusion based on a cycling maximal oxygen consumption (V̇O₂max) test (Visit 1), before resting exposure to 750 parts per billion (ppb) O₃ (Visit 2) to assess pulmonary function changes. During experimental trials (Visit 3 & 4), participants completed submaximal and maximal cycling exercise protocols exposed to both O₃ (170 ppb) and room air (RA, <10 ppb O₃). Results (n=20, V̇O₂max = 64.1 ± 7.0 ml/kg/min) indicated that pulmonary function was significantly reduced and development of adverse respiratory symptoms was increased following both resting and exercise O₃ exposure. No differences between conditions in ventilatory pattern or oxygen consumption (V̇O₂) were observed throughout submaximal exercise bouts. Paired t-tests comparing the last minute of a time-to-exhaustion (TTE) test at 105% of peak power showed lower relative V̇O₂ (p=0.003), tidal volume (p=0.007) and minute ventilation (p=0.047) during O₃ compared to RA conditions, with insignificant trends towards lower exercise time (p=0.092). As differences in relative V̇O₂ (p<0.001) and tidal volume (p=0.001) also existed when comparing each participant’s last shared minute between conditions, a respiratory limitation of oxygen transport to the exercising muscle groups during maximal exercise seems likely. A clearer understanding of the mechanisms that impact oxygen consumption during O₃ exposure and exercise is critical to maximizing performance in athletic events exposed to high levels of pollution.

Text

2023-08-30

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85708

Kinesiology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/