Internal Clock Determines Type of Stroke

Ivanhoe Newswire
Monday, August 21, 2006; 12:00 AM

(Ivanhoe Newswire) -- If you are at risk of having a stroke, you may want to keep your eye on the clock. New research reveals certain times of the day are more stroke prone than others and different types of strokes peak at different parts of the day.

Japanese researchers analyzed data from 13,000 patients who suffered one of three types of stokes -- cerebral infarction, intracerebral hemorrhage, or subarachnoid hemorrhage.

Early mornings and early evenings were the most common times for strokes to occur. All three types of strokes peaked between 6 a.m. and 8 a.m. and between 6 p.m. and 8 p.m.

Cerebral infarction -- when blood flow to brain arteries is restricted -- was the most common kind of stroke in the study. This kind of stroke had a higher peak in the morning than the other two types, according to the researchers. It also had a lower peak in the afternoon than the other two.

The other, more rare types of strokes were more likely to occur in the afternoon than cerebral infarctions. Part of the reason for this may be that low blood pressure is a risk factor for cerebral infarction. Blood pressure tends to be lowest during sleep.

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SOURCE: Journal of Neurology, Neurosurgery, and Psychiatry, published online Aug. 17, 2006