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Changes in respiratory function during a wilderness multisport endurance competition.

OBJECTIVE
To document the changes in respiratory function seen in competitors during a typical wilderness multisport endurance event.


METHODS
A prospective observational cohort study measuring forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) at baseline, midrace, and end of race in competitors in a 105-km ski/run/cycle/paddle race held midwinter in the mountains of Victoria, Australia.


RESULTS
Twenty-five adult subjects (22 men) between 20 and 42 years of age were studied. The mean decline in FEV1 was 15.1% (95% CI 10.3-19.8) and for FVC was 13.0% (95% CI 8.1-17.9). Fourteen (56%) of the 25 subjects had a >10% decline in FEV1 and FVC, and 7 (28%) of the 25 subjects had a >20% decline. In 9 control subjects, aged between 21 and 55 years, there was no significant change in FEV1 or FVC from prerace to end of race.


CONCLUSIONS
Significant declines in FEV1 and FVC are common during wilderness multisport endurance events. The focus of future research should be the etiology, which as yet remains speculative.