Date Published: February 6, 2019
Publisher: Public Library of Science
Author(s): Yukio Fujita, Motoo Yamauchi, Hiroki Uyama, Hideshi Oda, Michihito Igaki, Masanori Yoshikawa, Hiroshi Kimura, Pei-Lin Lee.
Mouth breathing could induce not only dry throat and eventually upper respiratory tract infection, but also snoring and obstructive sleep apnea, while nasal breathing is protective against those problems. Thus, one may want to explore an approach to modify habitual mouth breathing as preferable to nasal breathing. The aim of this study was to investigate the physiological effects of our newly developed mask on facilitation of nasal breathing.
Thirty seven healthy male volunteers were enrolled in a double blind, randomized, placebo-controlled crossover trial. Participants wore a newly developed heated humidification mask or non-heated-humidification mask (placebo) for 10-min each. Subjective feelings including dry nose, dry throat, nasal obstruction, ease to breathe, relaxation, calmness, and good feeling were asked before and after wearing each mask. In addition, the effects of masks on nasal resistance, breathing pattern, and heart rate variability were assessed.
Compared with the placebo mask, the heated humidification mask improved all components of subjective feelings except for ease to breathe; moreover, decreased nasal resistance and respiratory frequency accompanied a simultaneous increase in a surrogate maker for tidal volume. However, use of the heated humidification mask did not affect heart rate variability
Adding heated humidification to the nasopharynx could modulate breathing patterns with improvement of subjective experience and objective nasal resistance.
Humans breathe primarily through nose, but some breathe through the mouth. Mouth breathing could induce dry throat, while nasal breathing has protective effects on dry throat since the nasal mucosa adds heat and humidification to inspired air during inspiration. Dry throat and dry mouth are considered as risk factors for upper and lower respiratory tract infection, thus nasal breathing would be preferable to mouth breathing. Furthermore, mouth breathing enhances snoring and obstructive sleep apnea since genioglossus activity during nasal breathing has been reported to be higher compared to mouth breathing. Taken together, changing breathing route, which is from mouth to nose, would provide many benefits for humans.
In the current study, we demonstrated positive effects of our newly developed heated humidification mask. The heated humidification mask improved subjective feelings and decreased nasal resistance. More interestingly, the heated humidification mask modulated the breathing pattern, i.e., there appeared to be a decreased respiratory frequency accompanying simultaneous increases in surrogate tidal volume measures.
In conclusion, the heated humidification mask we newly developed could provide the beneficial effects for humans producing slow deep breathing and improving subjective feelings as well as nasal resistance. There is possibility that heated humidification mask leads mouth breathing toward nasal breathing.