Study on circadian rhythm of PEF and respiratory drive in nocturnal asthma

Objective:The aim of this study is to investigate the circadian rhythm of PEF and respiratory drive in nocturnal asthma.Methods:PEF and P 0.1 were measured at04:00,08:00,16:00,22:00in three groups:nocturnal asthma(n=10),non-nocturnal asthma(n=10)and healthy control subjects(n=10).Results:Both in nocturnal asthmatic group and control group,PEF was highest at16:00and lowest at04:00.In nocturnal asthma the difference was significant(P0.01).In control group,the difference was not significant(P0.05).In non-nocturnal asthma PEF did not decrease at night.P 0.1 did not take on circadian rhythm in all three groups.Conclusion:In nocturnal asthma,PEF takes on circadian rhythm.P 0.1 does not take on significant circadian rhythm in all three groups.