The external nasal dilator: style over function?

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

Respiratory function has become a global health priority. Not only is chronic respiratory disease a leading cause of worldwide morbidity and mortality, but the COVID-19 pandemic has heightened attention on respiratory health and the means of enhancing it. Subsequently, and inevitably, the respiratory system has become a target of the multi-trillion-dollar health and wellness industry. Numerous commercial, respiratory-related interventions are now coupled to therapeutic and/or ergogenic claims that vary in their plausibility: from the reasonable to the absurd. Moreover, legitimate and illegitimate claims are often conflated in a wellness space that lacks regulation. The abundance of interventions, the range of potential therapeutic targets in the respiratory system, and the wealth of research that varies in quality, all confound the ability for health and exercise professionals to make informed risk-to-benefit assessments with their patients and clients. This review focuses on numerous commercial interventions that purport to improve respiratory health, including nasal dilators, nasal breathing, and systematized breathing interventions (such as pursed-lips breathing), respiratory muscle training, canned oxygen, nutritional supplements, and inhaled L-menthol. For each intervention we describe the premise, examine the plausibility, and systematically contrast commercial claims against the published literature. The overarching aim is to assist health and exercise professionals to distinguish science from pseudoscience and make pragmatic and safe risk-to-benefit decisions.

External nasal dilators: definition, background, and current uses

Our goal was to revise the literature about external nasal dilators (ENDs) as to their definition, history, and current uses. We reviewed journals in the PubMed and MEDLINE databases. The current uses hereby presented and discussed are physical exercise, nasal congestion and sleep, snoring, pregnancy, cancer, and healthy individuals. Numerous studies have shown that ENDs increase the cross-sectional area of the nasal valve, reducing nasal resistance and transnasal inspiratory pressure and stabilizing the lateral nasal vestibule, avoiding its collapse during final inspiration. These effects also facilitate breathing and are beneficial to patients with nasal obstruction. Furthermore, END use is simple, noninvasive, painless, affordable, and bears minimum risk to the user. Most studies have limited sample size and are mainly focused on physical exercise. In conclusion, ENDs seem useful, so further studies involving potential effects on the performance of physical tests and improvements in sleep quality are necessary, especially in children and teenagers.

Evaluation of the effectiveness of the external nasal dilator strip in adolescent athletes: a randomized trial

OBJECTIVES

Evaluate the cardio-respiratory capacity (VO₂max.) and peak nasal inspiratory flow (PNIF) of healthy adolescent athletes with experimental and placebo external nasal dilator strips (ENDS).

METHODS

48 healthy adolescent athletes between the ages of 11 and 15 were evaluated and submitted to a cardio-respiratory 1000 m race in randomized order. The participants had peak nasal inspiratory flow (PNIF) values measured using the In-check-inspiratory flow meter. Dyspnea intensity was evaluated after a 1000 m test race using a labeled visual analog scale for dyspnea.

RESULTS

In relation to VO2max., when the participants used the experimental ENDS, significantly higher means were noted than when the placebo was used (53.0 ± 4.2 mL/kg min(-1) and 51.2 ± 5.5 mL/kg min(-1), respectively) (p<0.05). In relation to PNIF, there was a statistically significant difference between the experimental and placebo ENDS result, that being, 123 ± 38 L/min and 116 ± 38 L/min, respectively (p<0.05). The dyspnea perceived by the participants was representatively lesser in the experimental ENDS condition compared to the placebo after the cardio-respiratory test (p<0.05).

CONCLUSIONS

The results suggest that the ENDS improve maximal oxygen uptake, nasal patency and respiratory effort in healthy adolescent athletes after submaximal exercise.