Circadian variations of bronchoconstriction in asthmatic children

• Published in: La Pediatria medica e chirurgica Vol. 10; no. 3; p. 259
• Main Authors: Battistini, A, Pisi, G, Padula, G, Marvasi, R, Grzincich, G L
• Format: Journal Article
• Language: Italian
• Published: Italy 01.05.1988
• Subjects: Adolescent; Asthma - physiopathology; Bronchi - physiopathology; Child; Child, Preschool; Circadian Rhythm; Female; Forced Expiratory Volume; Humans; Male; Spirometry; Vital Capacity
• ISSN: 0391-5387

In order to determine the magnitude of circadian variations in bronchoconstriction, we examined modifications of the spirometry observed during the 24-hr in a group of asthmatic (31 males, mean age = 8 years, 6 months). Particular attention was paid to the forced expiratory volume in 1 sec. (FEV1) and the forced vital capacity (FVC). We were thus able to compare in single patients 43 spirometry pairs between morning (between 8 and 10 am) and early afternoon (between 1 and 4 pm), 46 pairs between morning and evening (between 6 and 10 pm) and 54 between 2 consecutive mornings. The results of this study, substantially similar for the FEV1 and the FVC, show that the mean values obtained at different hours during the day and in two consecutive mornings were almost superimposable. On the other hand, the mean values and the standard deviations of the differences between two determinations in single patients are high. The percentage of patients who present significant modifications (greater than 10%) of FEV1 or of FVC at different hours of the day is also quite high. Moreover these variations seem directly related to the baseline spirometric value. Although the literature frequently outlines the existence of a circadian rhythm in the modifications or airways patency (maximum bronchoconstriction in the morning and minimum in the evening), in the asthmatic, however, the fast variations in the bronchial tone can be such as to mask this cyclic rhythm.