H₂O₂ and NO₂⁻ in Exhaled Breath Condensate Increase After a Wheelchair Rugby Match in Paralympic Athletes: A Possible Effect of Functional Classification

Spinal cord injury (SCI) is associated with respiratory dysfunction, chronic inflammation, and oxidative stress, and can increase pulmonary tissue stress during exercise. Thus, hydrogen peroxide (H₂O₂) and nitrite (NO₂⁻) concentrations in exhaled breath condensate (EBC) were compared during an official wheelchair rugby match. 14 males and two females with SCI (33.3 ± 6.5 years), anthropometry, baseline spirometry, and the International Wheelchair Rugby Federation classification (IWRF) were recorded. Playing time (23.6 ± 7.49 min), Borg scale (4.3 ± 1.64), and [H₂O₂] EBC and [NO₂⁻] EBC were determined before and 20 min after the match. In the total sample, [H₂O₂] EBC and [NO₂⁻] EBC increased post-match (p = 0.0042 and p = 0.031, respectively). When segmented according to IWRF classification, the highest functional capacity, H group (>1.5 points; n = 11) increased its [H₂O₂] EBC per exercise (p = 0.0029) and showed a trend for [NO₂⁻] EBC (p = 0.09), while the lowest classification, L group (≤1.5 points; n = 5) showed a higher baseline concentration in both EBC markers with no changes per exercise. Baseline IWRF classification was inversely correlated with [H₂O₂] EBC, while body mass index (BMI) was positively associated with [NO₂⁻] EBC. In conclusion, in the sample analyzed, a short period of moderate intensity during a wheelchair rugby match increases H₂O₂ and NO₂⁻ in the airway with a potentially greater effect in SCI athletes with better functional capacity; it remains to be determined whether this phenomenon corresponds to a physiological or pathological process.