At enrolment, six blood pressure measurements for each participant were taken in various physical positions, including when lying down and after standing up.
The 120 participants with the highest rise (top 10 percent) in blood pressure upon standing averaged an 11.4 mm Hg increase; all increases in this group were greater than 6.5 mm Hg.
The remaining participants averaged a 3.8 mm Hg fall in systolic blood pressure upon standing.
The researchers compared heart disease risk factors, laboratory measures and the occurrence of major cardiovascular events (heart attack, heart-related chest pain, stroke, aneurysm of the aortic artery, clogged peripheral arteries) and chronic kidney disease among participants in the two groups.
In some analyses, the development of atrial fibrillation, an arrhythmia that is a major risk factor for stroke, was also noted. Results were adjusted for age, gender, parental history of heart disease, and several lifestyle factors and measurements taken during study enrolment.