In older people who have high blood pressure, a sharp increase in blood pressure in the morning increases risk of stroke and is linked to brain lesions known as "silent" strokes, according to a study in Circulation: Journal of the American Heart Association.
The study is the first to show that excessive morning blood pressure surge is a predictor of stroke in elderly people with high blood pressure, according to researchers at Jichi Medical School in Tochigi, Japan.
The researchers followed 519 Japanese patients with high blood pressure, average age 72, for about 41 months. They all underwent 24-hour continuous blood pressure monitoring and a magnetic resonance imaging scan to determine presence of brain lesions that indicate a "silent" stroke. The participants were then divided into the morning surge group and the non-surge group. They found 57 percent of the surge group were likely to have multiple silent strokes, compared to 33 percent of the non-surge group. After adjusting for age and ambulatory blood pressure, the relative risk of stroke for people with a morning surge was nearly three times higher than for those without the surge.
The researchers called for further investigation in other populations and a large, randomized controlled trial using antihypertensive drugs to suppress the morning surge of blood pressure.