title: Diurnal variation in pulmonary diffusing capacity and expiratory volumes.
abstract: The pulmonary diffusing capacity for Carbonmonoxide (DLCO) was measured in 20 normal volunteers of either sex at 9 a.m., 12 noon and 5 p.m. Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were also determined after each DLCO measurement. There was a fall in the mean noon value of the diffusing capacity of the lungs which was statistically significant. The value at 5 p.m. was almost same as the noon value. The forced expiratory volume in one second and the forced vital capacity followed a similar trend. The DLCO, FEV1 and FVC appear to exhibit a diurnal rhythm.
mesh_terms: D000328:Adult; D002248:Carbon Monoxide / Q000032:analysis; D002940:Circadian Rhythm; D004837:Epinephrine / Q000097:blood; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011187:Posture; D011653:Pulmonary Diffusing Capacity; D012907:Smoking / Q000503:physiopathology; D013997:Time Factors; D014797:Vital Capacity
chemical_list: D002248:Carbon Monoxide; D009638:Norepinephrine; D004837:Epinephrine