Respiratory NO metabolism in skiers and biathlonists with exercise-induced bronchospasm

Abstract

The aim of the study was to investigate respiratory NO metabolism in adolescent EIB-positive and EIB-negative athletes in different periods of the annual training cycle. Skiers and biathlonists aged 12 – 19 were studied in precompetitive (n=92) and competitive (n=78) periods. Control group included 64 healthy volunteers not involved in sports. Pulmonary function test was analyzed at baseline and after the training or competition at subfreezing temperature. FeNO was measured in the exhaled air initially and after the exercise. Pre- and post-exercise total NO2-/NO3- and 3-nitrotyrosine levels were assessed in EBC. Pre- and post-exercise FeNO, total NO2-/NO3- and 3-nitrotyrosine levels were significantly higher in athletes compared with control group (p<0.05). These parameters were compared in skiers and biathlonists during different periods of annual training cycle. In competitive period athletes demonstrated higher 3-nitrotyrosine EBC level (14.8 vs 8.1ng/ml; p<0.01) than those in precompetitive period. Precompetitive period was characterized by higher total NO2-/NO3- level (10.8 vs 7.5mkmol/l; p=0.01). 6,4% and 6,5% of athletes in competitive and precompetitive periods respectively had a post-exercise decrease in FEV1 of ≥ 10%. EIB prevalence in controls was similar. In EIB-positive athletes significantly lower pre-exercise FeNO levels were found (9.4 vs 14.2ppb, p=0.03) compared to EIB-negative group. Conclusion: Present study revealed similar EIB prevalence in winter sport athletes and non-athletic controls. Obtained results support the possible role of NO and its metabolites in EIB development. The levels of FeNO, NO2-/NO3-, 3-nitrotyrosine in athletes are described as well.