Does the external nasal dilator strip help in sports activity? A systematic review and meta-analysis

Background Numerous studies have shown that the external nasal dilator (END) increases the cross sectional area of the nasal valve, thereby reducing nasal resistance, transnasal inspiratory pressure, stabilizing the lateral nasal vestibule, and preventing its collapse during final inhalation. Objectives Our objective was to carry out a systematic review of the literature and meta-analysis on the effects of the END during physical exercise. Methods After selecting articles in the PubMed, Cochrane Library and EMBASE databases, 624 studies were identified. However, after applying the inclusion and exclusion criteria, 19 articles were considered eligible for review. Results Those studies included in the meta-analysis, the maximal oxygen uptake (VO 2 max.) outcome was assessed in 168 participants in which no statistically significant difference was found, MD (95% CI) = 0.86 [− 0.43, 2.15], p = 0.19, and I 2 = 0%. The heart rate (HR) outcome was assessed in 138 participants in which no statistically significant difference was found, MD (95% CI) = 0.02 [− 3.19, 3.22], p = 0.99, and I 2 = 0%. The rating of perceived exertion (RPE) outcome was assessed in 92 participants in which no statistically significant difference was found, MD (95% CI) = − 0.12 [− 0.52, 0.28], p = 0.56, and I 2 = 27%. Conclusions The external nasal dilator strip showed no improvement in VO 2 max., HR and RPE outcomes in healthy individuals during exercise.