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

Abstract

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.

Distinguishing science from pseudoscience in commercial respiratory interventions: an evidence-based guide for health and exercise professionals

“…On the premise that ENDs increase some measures of nasal patency and nasal inspiratory flow, their potential to improve exercise capacity has also been explored. Despite a few reports of favorable outcomes (Griffin et al 1997;Dinardi et al 2013Dinardi et al , 2017, a recent systematic review and meta-analysis of 19 articles concluded that ENDs elicited "no improvement in VO 2 max , HR and RPE outcomes in healthy individuals during [maximal or submaximal] exercise" (Dinardi et al 2021). Other studies, using esophageal balloon catheters, showed no effect of ENDs on inspiratory elastic work, inspiratory resistive work, or expiratory resistive work during submaximal or maximal exercise (O'Kroy et al 2001).…”

Nasal Injuries and Issues in Athletes

“…Currently, there is conflicting evidence as to the objective improvement provided by external nasal dilators (ENDs) or internal nasal dilators (INDs) for parameters such as peak nasal inspiratory flow (PNIF), maximal oxygen uptake (V ˙O2max ), heart rate (HR), and rate of perceived exertion (RPE). For instance, a group of researchers conducted a meta-analysis including 19 studies on the impact of ENDs during exercise for healthy participants, noting no significant improvement in V ˙O2max , HR, and RPE compared with placebo groups (16). Other studies have noted improvement in nasal function measurements like PNIF or nasal patency with ENDs or INDs use, but with relatively small sample sizes and no clear performance benefit (17,18).…”

Human performance augmentation: the importance of integrative physiological quantification

“…However, it has not been established that nasal airflow resistance impacts maximal oxygen uptake in healthy adults. More than a dozen research studies have investigated the potential for external nasal dilator strips to augment maximal oxygen uptake in healthy adults but, perhaps unsurprisingly, a recent meta‐analysis found no improvement (Dinardi et al., 2021). A valuable issue to consider for any potential performance‐augmenting technology is whether it affects a mechanism associated with performance limitation in the target population.…”