WILLIAMSBURG, Va. -- Researchers at Duke University Medical Center have
found that the more physically fit a woman is, independent of regular exercise,
the lower her blood pressure level is during a stressful day at work.
The findings are significant because high blood pressure at work is associated
with a greater risk of heart disease than high blood pressure in the clinic
or in a physician's office, according to Elizabeth C. D. Gullette, a behavioral
medicine researcher and project coordinator of the study.
"Our findings suggest that for working women, physical fitness may
buffer against the work-related stress that causes blood pressure to rise,"
Gullette said. The subjects in the study were mildly hypertensive working
women, aged 31 to 57, who were moderately overweight and who had not exercised
regularly for at least six months.
Results of the study, funded by a five-year grant from the National Heart,
Lung and Blood Institute, were prepared for presentation at the annual meeting
of the American Psychosomatic Society.
In the study, 24 women were given exercise treadmill tests to determine
their precise levels of fitness. The women also wore portable blood pressure
monitors at home and at work for a 15-hour period to assess changes in blood
pressure during routine activities.
Women who were more physically fit, as determined by greater oxygen consumption
during the exercise test, had lower blood pressure levels at work than women
who were less physically fit. The physically fit women also had smaller
blood pressure changes between home and work environments than unfit women.
Researchers said the rise in blood pressure at work suggests that unfit
women react more strongly and negatively to work pressures than physically
fit women.
High blood pressure at work is dangerous because studies have shown it
to be more predictive of left ventricular hypertrophy (LVH), or enlargement
of the heart's left ventricle, than home blood pressure or blood pressure
measured in the clinic.
LVH is a major risk factor for coronary artery disease and may be a more
significant predictor than cigarette smoking or high cholesterol levels,
according to numerous studies, including one published in the May 1995 issue
of the Journal of the American Medical Association.
The researchers now are conducting a longitudinal study of women enrolled
in an exercise program to determine whether exercise training can further
reduce blood pressure levels at work.
"If fit women are better able to remain calm in the face of work-related
stress, then they have less of a burden on their cardiovascular system,
which in turn lowers their risk of heart disease," Gullette said.