OBJECTIVE: Conducting a prospective pilot study to investigate the effect of temperature-controlled radiofrequency treatment of the nasal valve in endurance athletes with internal nasal valve collapse. MATERIAL AND METHODS: Twenty-five endurance athletes with nasal valve collapse were recruited from 2018 to 2020. Eight of the 25 patients dropped out of the study due to different reasons (injured due to non-nasal causes before postoperative measurement, refusal of surgery in the short term, termination due to corona pandemic), so that 17 study participants completed the study. We investigated NOSE questionnaire and rhinomanometry before and after radiofrequency treatment of the internal nasal valve (Vivaer radiofrequency probe). In addition, an exhaustive treadmill test before and after radiofrequency treatment was performed. The collected measurements were registered and compared with paired t-test. A Cohen's dz was performed for significant results. The normal distribution was confirmed by using the Kolmogorov-Smirnov test and Q-Q plots. RESULTS: There was a significant improvement in the NOSE score (P<
0.001, Cohen's dz=1.03) and no serious side effects. No significant differences were seen before and after the treatment in rhinomanometry and spiroergometry. CONCLUSION: Due to the low side effects and the subjective improvement in nasal breathing according to the NOSE score, the technique could perhaps represent a promising non-invasive therapy for improving nasal breathing in endurance athletes. However, no significant improvement was observed in the objective parameters. Larger study cohorts are required to investigate the effect in more detail.