title: Chronobiology and asthma. I. Day-night differences in bronchial patency and dyspnea and circadian rhythm dependencies.
abstract: The symptoms of allergic asthmatic patients typically worsen during the night, especially during the early morning hours. Although 24-hour variations in the environment contribute to the intensification of the asthmatic condition nocturnally, environmental changes themselves do not fully explain the temporal aspects of this disease. Circadian (about 24-hour) rhythms in critical bioprocesses constitute significant contributory factors. The exacerbation of asthma during the night represents the changing status of biological functioning due to circadian rhythms in bronchial patency; airways hyperreactivity to acetylcholine, histamine, and house dust; and plasma cortisol, epinephrine, histamine, and cyclic AMP, among others.
mesh_terms: D001249:Asthma / Q000503:physiopathology*; D001980:Bronchi / Q000503:physiopathology*; D002940:Circadian Rhythm; D004417:Dyspnea / Q000503:physiopathology*; D004777:Environment; D006801:Humans