Circadian rhythm of peak expiratory flow rate in healthy north Indian men.

Peak expiratory flow rate (PEFR) variability follows a specific pattern in asthmatics as well as in healthy individuals. There is scarcity of data for Indian healthy subjects. The PEFR (L/min.) was measured with Wright's portable peak flow meter at 05:00, 8:00, 11:00, 14:00, 17:00, 20:00 and 23:00 hours in 42 healthy, non-smoking adults of age group between 18-26 years. The variability of PEFR revealed a circadian pattern. PEFR levels tend to increase from morning at 5:00 hours till evening at 17:00 hours, with peak PEFR in evening at 17:00 hours, after which there was a progressive fall in PEFR levels, till morning 5:00 hours. This study provides the preliminary reference data of circadian pattern of PEFR in healthy individuals.