| dc.description.abstract | Purpose The aerobic exercise affects the respiratory redox-state. The influence of different relative humidity (RH) levels on the formation of respiratory reactive chemical species associated with redox-state altered by exercise has been poorly explored. Our aim was to evaluate the effect of two different RH conditions (40% vs. 90%) on the concentration of hydrogen peroxide and nitrite in exhaled breath condensate ([H2O2](EBC)and [NO2-](EBC)) and spirometry parameters in recreational cyclists. Methods Sixteen men and women (12/4) (mean age +/- SD: 23.5 +/- 2.2 years) completed 60-min of cycling at 166.3 +/- 26.9 watts (70% of maximum load of (V) over dotO(2)-max. test, 49.3 +/- 7.6 mL center dot min(-1)center dot kg(-1)) at random 40%-RH and 90%-RH conditions separated by 7 days. The two-way RM-ANOVA test was applied to compare [H2O2](EBC), [NO2-](EBC), [NO2-](EBC)/[NO2-](Plasma)at rest and 80-min post-exercise (80-post); and spirometry parameters at rest, 20-post and 80-post.. Results The interaction of factors (humidity x time) was significant in [H2O2](EBC), [NO2-](EBC), [NO2-](EBC)/[NO2-](Plasma)(p = 0.005,p = 0.030,p = 0.043, respectively). At 40%-RH conditions, the same parameters were higher in 80-post than at rest (p < 0.001,p = 0.001,p = 0.014, respectively). At the same time, the [H2O2](EBC)and [NO2-](EBC)/[NO2-](Plasma)were higher in 40%-RH than 90%-RH (p = 0.010,p < 0.001, respectively). The interaction was significant in FEV1(p = 0.013) and FEF25-75%(p = 0.023), but not in FEV1/FVC (p = 0.362). At 80-post, the changes are kept in 90%-RH (p < 0.001), diminishing in 40%-RH being similar to rest. Conclusion In recreational cyclists, 90%-RH prevents the increase of hydrogen peroxide and nitrite in exhaled breath condensate samples observed at 40%-RH and prolonging the bronchodilation until 80-post cycling exercise. | |
