Humidity prevents the exercise-induced formation of hydrogen peroxide and nitrite in exhaled breath condensate in recreational cyclists

H2O2 Concentration in Exhaled Breath Condensate Increases After Phonotrauma: A Promise of Noninvasive Monitoring?

PURPOSE

The present study was designed to observe the concentration of hydrogen peroxide (H2O2) in exhaled breath condensate (EBC) after induced phonotrauma.

METHODS

Thirty-five participants were randomly assigned to one of two conditions (1) Vocal demand and (2) Control. Participants in the experimental group (vocal demand) were asked to read aloud some texts during 1 hour, at 85-90 dB. Inflammation (H2O2 from exhaled breath condensate), acoustic, aerodynamic, and subjective measures were obtained at four time points: before vocal demand (baseline), immediately after baseline, 4-hour after baseline, and 24 hours after baseline. The same acquisition process was implemented for subjects in control group, except that they were not asked to engage in any vocal demand tasks at all.

RESULTS

As for biological samples, a significant effect for group was observed. Higher values were found for participants in experimental condition. Significant differences were observed for within contrasts in the experimental group, namely 4 hours against baseline, 4 hours against immediately post, and 24 hours against 4 hours. Instrumental outcomes did not show significant differences across the different conditions at any time points. Self-reported measures (vocal fatigue and sensation of muscle tension) showed a significant main effect for group and main effect for condition.

CONCLUSIONS

Intense vocal demand causes an increase in the concentration of H2O2 obtained from EBC at four hours after baseline, which is compatible with the generation of an inflammatory process in the vocal folds (phonotrauma). Moreover, the increase in the sensation of vocal fatigue and muscle tension after demand tasks seems to be an immediate reaction that did not match in time with the increment of H2O2 concentration.

Sex-Differences in the Oxygenation Levels of Intercostal and Vastus Lateralis Muscles During Incremental Exercise

This study aimed to examine sex differences in oxygen saturation in respiratory (SmO₂-m.intercostales) and locomotor muscles (SmO₂-m.vastus lateralis) while performing physical exercise. Twenty-five (12 women) healthy and physically active participants were evaluated during an incremental test with a cycle ergometer, while ventilatory variables [lung ventilation ( V . E), tidal volume (Vt), and respiratory rate (RR)] were acquired through the breath-by-breath method. SmO₂ was acquired using the MOXY^® devices on the m.intercostales and m.vastus lateralis. A two-way ANOVA (sex × time) indicated that women showed a greater significant decrease of SmO₂-m.intercostales, and men showed a greater significant decrease of SmO₂-m.vastus lateralis. Additionally, women reached a higher level of ΔSmO₂-m.intercostales normalized to V . E (L⋅min^-1) (p < 0.001), whereas men had a higher level of ΔSmO₂-m.vastus lateralis normalized to peak workload-to-weight (watts⋅kg^-1, PtW) (p = 0.049), as confirmed by Student's t-test. During an incremental physical exercise, women experienced a greater cost of breathing, reflected by greater deoxygenation of the respiratory muscles, whereas men had a higher peripheral load, indicated by greater deoxygenation of the locomotor muscles.