The nasal cavity and turbinates play important physiological functions by filtering, warming and humidifying inhaled air. Paranasal sinuses continually produce nitric oxide (NO), a reactive oxygen species that diffuses to the bronchi and lungs to produce bronchodilatory and vasodilatory effects. Studies indicate that NO may also help to reduce respiratory tract infection by inactivating viruses and inhibiting their replication in epithelial cells. In view of the pandemic caused by the novel coronavirus (SARS-CoV-2), clinical trials have been designed to examine the effects of inhaled nitric oxide in COVID-19 subjects. We discuss here additional lifestyle factors such as mouth breathing which may affect the antiviral response against SARS-CoV-2 by bypassing the filtering effect of the nose and by decreasing NO levels in the airways. Simple devices that promote nasal breathing during sleep may help prevent the common cold, suggesting potential benefits against coronavirus infection. In the absence of effective treatments against COVID-19, the alternative strategies proposed here should be considered and studied in more detail.

鼻腔和鼻甲通过过滤，加热和加湿吸入的空气发挥重要的生理功能。鼻旁窦持续产生一氧化氮（NO），一种活性氧扩散到支气管和肺，产生支气管扩张和血管扩张作用。研究表明，NO还可以通过灭活病毒并抑制其在上皮细胞中的复制来帮助减少呼吸道感染。鉴于新型冠状病毒（SARS-CoV-2）引起的大流行，已设计了临床试验来检查吸入一氧化氮对COVID-19受试者的影响。我们在这里讨论其他生活方式因素，例如口呼吸，可能会绕过鼻子的过滤作用并降低呼吸道中的NO含量，从而影响针对SARS-CoV-2的抗病毒反应。简单的设备可以在睡眠时促进鼻呼吸，有助于预防普通感冒，这表明对冠状病毒感染有潜在的好处。如果没有针对COVID-19的有效治疗方法，则应考虑和详细研究此处提出的替代策略。