March 3, 2003 -- Morning may be the most dangerous time of the day for older people with high blood pressure. A new study shows many of the elderly have morning surges in blood pressure that can drastically increase their risk of stroke.
Researchers found that people whose blood pressure spikes in the morning are three times as likely to suffer a stroke compared with others, and they may require longer-lasting blood pressure-lowering medications.
"This is the first study to show that an excessive morning blood pressure is a predictor of stroke in elderly people with high blood pressure," says researcher Kazuomi Kario, MD, of the department of cardiology at Jichi Medical School in Tochigi, Japan, in a news release.
In the study, researchers followed 519 elderly Japanese high blood pressure patients with an average age of 72 for about 41 months. Each of the participants had their blood pressure monitored over a 24-hour period and underwent magnetic resonance imaging (MRI) scans to determine if they had brain lesions, which serve as evidence of "silent" or mild strokes that result in slight brain damage.
Researchers found 53 of the patients had blood pressure levels that rose by 55 points or more in the morning compared with their lowest sleeping blood pressure levels. The average morning blood pressure surge among this group was 69 points, compared with a rise of only 29 points among the other 466 patients.
Even after adjusting for age and other stroke risk factors, the study showed that those who had the biggest morning surges were much more likely to have suffered a stroke compared with the others (19% vs. 7%). In addition, the morning surge group was much more likely to have suffered multiple "silent" strokes compared with the other patients (57% vs. 33%), according to their MRI scans.
The results appear in today's issue of Circulation: Journal of the American Heart Association.
In an editorial that accompanies the study, Norman M. Kaplan, MD, of the University of Texas Southwestern Medical Center at Dallas, says this is the largest and most definitive study to date to show an increased risk of stroke linked to a morning surge in blood pressure.
"Some days it just doesn't pay to get out of bed," writes Kaplan. In light of these findings, Kaplan says that people who have morning blood pressure surges should use blood pressure-lowering medications that provide 24-hour relief. These patients should also be encouraged to monitor their blood pressure at home to ensure their therapy is providing adequate protection from this additional risk factor.