It's not a huge increase -- but it's enough to confer a substantial risk of heart disease, find Els Clays, MSc, of Ghent University in Belgium, and colleagues.
As part of the Belgian Job Stress Project, the researchers strapped blood pressure monitors to the arms of 89 middle-aged men and women found to have particularly stressful jobs. Another 89 men and women not experiencing job stress also volunteered for the study.
After adjusting for other factors that affect blood pressure -- sex, age, weight, physical job demands, high stress outside work, and physical activity -- the high-job-stress men and women had higher blood pressure.
Their blood pressure was highest on the job, when they had 5.9/3.0 mm Hg higher blood pressure than the nonstressed workers did. But the stressed-out workers also had higher blood pressure while at home, including while they were sleeping.
Clays and colleagues say the main factor behind work-related stress is something they call "high job strain."
This happens when a person is exposed to "high psychological demands" in combination with low job control. Study data suggest that it is the "low job control" aspect of job strain that most affects blood pressure.
The findings appear in the April issue of the Journal of Occupational and Environmental Medicine.