Risk of stroke greater in morning hours.




Archives of Neurology

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Consumer Data: Stroke
Professional Data: Stroke


The term "stroke" or "paralytic stroke" is commonly used to describe a sudden problem with the brain that is usually related to its blood supply. A "stroke," therefore, can be due to ischemia (decreased blood supply), infarction (interrupted blood supply), or hemorrhage (severe bleeding). All three of these causes (ischemia, infarction, or hemorrhage) would be due to cerebrovascular disease (disease related to the blood supply to the brain).

While many risk factors have been identified that increases a person's risk for stroke, hypertension (high blood pressure), is by far, the greatest. Hypertension has been identified as a factor in 70 percent of all strokes. A problem with heart function is the next most important single treatable risk factor for stroke. Individuals with heart diseases such as coronary heart disease, congestive heart failure, enlargement of the left ventricle, and arrhythmias (specifically atrial fibrillation) have more than twice the stroke risk compared to those with normal heart function.1 Other groups considered at higher risk for stroke include those with sickle cell disease, and middle-aged male patients with a history of stroke on their mother's side of the family. Patients with increased blood thickness are also considered at higher risk for stroke.

A recent group of researchers investigated the role of the circadian cycle in onset of ischemic stroke. The study, published in the Archives of Neurology, involved 1,656 stroke patients. The demographical, medical, and pathophysiological factors of the circadian variation were recorded. As in pervious studies, the results showed that most ischemic strokes occurred in the morning. A second peak of stroke took place in the evening. Concluding, the authors noted that the circadian variability of blood pressure might have a role in the onset of stroke. Also, future preventative measures could target morning risk factors that contribute to stroke.2


1. Bradberry JC. Stroke, In: DiPiro et al eds, Pharmacotherapy, A Pathophysiologic Approach. 4th ed. Stamford, CT: Appleton & Lange; 1999:327-347.
2. Casetta L. Patient Demographic and Clinical Features and Circadian Variation in Onset of Ischemic Stroke. Arch Neurol. Jan 2002;59:48-53.