Asthma is characterized by inflammation and narrowing of the airways, which can lead to breathing difficulties and other symptoms. Nasal breathing can help reduce the severity and frequency of asthma symptoms, mainly if triggered during exercise. When sleeping with a nasal dilator which helps to open the nose for easier breathing, the patients woke up with asthma on 17 of 75 nights as compared with 32 of 75 when sleeping without the device. Reduced nocturnal asthma was observed by 12 patients and less need for asthma medication at night by 7.
Peterson B, Theman K. Reduced nocturnal asthma by improved nasal breathing. Acta Otolaryngol. 1996 May;116(3):490-2. doi: 10.3109/00016489609137878. PMID: 8790753.