Very Early-Morning Increase in Onset of Ischemic Stroke

Abstract

A study was conducted on 525 consecutive patients ranging in age from 36 years to 86 years to determine whether diurnal variation occurs in the onset of acute ischemic stroke. There was a clear (D(max)=0.19, P<0.01) diurnal variation with a significant (t=-4.96, P<0.001) peak between four a.m. and six a.m. Strokes occurred more often during the two hours following awakening than during any other time of the day. The peak time of ischemic stroke in our study was about two hours earlier than in previous reports, probably because of the different waking times of the studied populations. We concluded that the time of awakening influences the circadian distribution rather than the time of day itself.