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September 15, 2001
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Blood Pressure Measures During Exercise Can Indicate Unhealthy Hearts
A blood pressure reading taken during exercise is a more accurate test for
early heart disease than one taken at rest, according to a study presented Sept.
14 at the annual meeting of the American Association of Cardiovascular and Pulmonary
Rehabilitation (AACVPR) in Minneapolis.
The study, conducted by researchers at The Johns Hopkins University School
of Medicine in Baltimore, showed that a high pulse pressure – defined as
the difference between systolic blood pressure (the upper number) and diastolic
blood pressure (the lower number) – during exercise was associated with
a dysfunction of the endothelial cells lining the blood vessels. These cells
control the ability of the blood vessels to dilate, or expand, which allows
more blood to flow during periods of stress. Increased pulse pressure is also
an indicator of blood-vessel stiffening, which may be a marker of early heart
disease. Recent epidemiological studies have shown that pulse pressure is the
leading risk factor for cardiovascular disease in the elderly.
"Most clinicians focus on the patient's blood pressure during rest, but
our study shows that exaggerated blood pressure during exercise is a more sensitive
marker for resistance to blood flow through the arteries, which is a possible
sign of atherosclerosis (hardening of the arteries)," says Kerry J. Stewart,
Ed.D., lead author of the study and director of cardiac rehabilitation and clinical
exercise physiology at Hopkins. "The higher the pulse pressure in response
to exercise, the more likely the patient was to have blood vessels that did
not expand as expected."
If cells lining the blood vessels are unable to respond well to the increase in blood flow associated with stress and exercise, the heart must work harder and can become enlarged, Stewart says. An enlarged heart heightens a person's risk of heart attack, stroke or heart failure.
For the study, Stewart and colleagues evaluated 35 adults, ages 55 to 75, who
had untreated mild hypertension but were otherwise healthy. Researchers measured
the participants' resting blood pressure during four or five visits at least
one week apart, then compared those measurements to blood pressure readings
recorded during maximal effort treadmill exercise tests. They also used ultrasound
to measure how well the vessels in the subjects' arms would expand in response
to stress.
Other authors of the study were Anita C. Bacher, Katherine L. Turner, Jamie R. DeRegis, Harry A. Silber, Edward P. Shapiro, Jidong Sung and Pamela Ouyang.
Established in 1985, the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR) aims to promote health and prevent disease. AACVPR represents more than 3,000 health care professionals worldwide engaged in education, prevention, rehabilitation, research and disease management activities in cardiovascular and pulmonary rehabilitation and prevention programs.
Stewart, K.J. et al., "Pulse Pressure at Maximal Exercise is Associated with Endothelial Function."
Related Web sites:
Johns Hopkins Heart Health: http://www.jhbmc.jhu.edu/cardiology/rehab/hh_timonium.htm
Information on Heart Disease Treatments at Johns Hopkins: http://www.hopkinsmedicine.org/heartdisease.html
American Association of Cardiovascular and Pulmonary Rehabilitation: http://www.aacvpr.org