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Exercise, Stress Management Show Physiological Benefits for Heart Patients


Duke Health News 919-660-1306

DURHAM, N.C. -- Behavior modification techniques such as
exercise and stress management can not only reduce the levels
of depression and distress in heart patients, but can also
improve physiological markers of cardiovascular health,
according to the results of a randomized controlled trial
conducted by Duke University Medical Center researchers.

According to the research team, this may be the first
randomized trial to demonstrate that a non-pharmaceutical
approach can have positive effects on such physiological
determinants of cardiovascular health as blood flow to heart,
the responsiveness of the lining of blood vessels and the
ability of the cardiovascular system to regulate surges in
blood pressure.

"While studies have shown that psychosocial factors such as
depression, stress and anxiety place heart patients at a much
greater risk of suffering future cardiac events or dying, few
have looked at the effects of modifying psychosocial factors,"
said Duke medical psychologist James Blumenthal, Ph.D., lead
author of a study appearing in the April 6, 2005 issue of the
Journal of the American Medical Association. The trial was
supported by a $4.3 million grant from the National Institutes
of Health.

"Our results suggest that exercise and stress management
training offer considerable promise for patients with heart
disease by not only improving psychosocial functioning and
reactions to mental and physical stressors, but also by
modifying important bio-markers of risk that may translate into
improved clinical outcomes," he said.

The Duke trial enrolled 134 patients with stable heart
disease and randomized them to one of three groups – exercise,
stress management or standard medical therapy. Patients
randomized to the exercise group participated in 35 minutes of
supervised aerobic exercise training three times a week for 16
weeks. Those in the stress management arm received 16 weekly
1.5-hour classes designed to help patients recognize the
sources of stress in their everyday lives and to teach them
strategies to respond more adaptively to those stresses.

Patients enrolled had stable heart disease, meaning they did
not experience chest pain while at rest, and exhibited evidence
of myocardial ischemia, or reduced blood flow to the heart,
during exercise. All participants underwent a battery of
psychological and physiological testing before randomization,
which was repeated four months later.

One of the physiological markers studied was the
endothelium, which forms the inner lining of the blood vessels
and controls how the vessels reacted to changes in blood flow
and pressure. The researchers took ultrasound images of the
brachial artery of the arm before and after a tourniquet was
applied and released to determine how the vessels responded.
Healthy arteries will dilate to accommodate the increased blood
flow, while diseased arteries are less responsive, the
researchers said.

In these tests of flow-mediated dilation, patients who
received the behavioral treatments displayed nearly a 25
percent improvement when compared to those patients who only
received usual medical care.

"To our knowledge, this is the first study to show that
stress management might reduce cardiovascular risk in part
through beneficial effects on vascular endothelial function,"
Blumenthal said. "This is a level of improvement is comparable
to that achieved in drug trials. For that reason, these
findings add additional support for the use of
non-pharmaceutical approaches to treating patients with heart

The researchers also found that patients who received
exercise training or stress management had improved baroreflex
sensitivity, a phenomenon by which receptors located along the
walls of blood vessels respond to changes in blood pressure.
These receptors are connected to the heart by nerves, which
carry the message to pump faster or slower in response to
pressure changes.

"This finding is important because past studies have
demonstrated that abnormally low baroreflex sensitivity has
been shown to be associated with worse outcomes for patients
with heart disease--improvement may produce clinical benefits,"
Blumenthal said.

Additionally, the researchers measured changes in the left
ventricle -- the pumping chamber of the heart -- during periods
of both mental and physical stress. The research team used
radionuclide imaging tests to identify wall motion
abnormalities (WMAs). These WMAs, or areas of abnormal
contractions of the left ventricle, are known indicators of

"While there was no difference in WMA scores between the
three groups during mental stress testing, among the subgroup
of patients who had mental stress-induced WMAs before
treatment, those in the exercise and stress management groups
had lower WMA scores after treatment compared to patients in
usual care."

Other findings, which were expected, showed that patients in
the exercise group had the largest improvements in such
measures as exercise duration and aerobic capacity. For the
psychosocial tests, the researchers found that exercise and
stress management had reduced general distress and depression
compared to usual care controls.

Future studies are planned to determine if stress management
and exercise together have an even greater positive effect on
these markers of cardiovascular health. The researchers also
said further investigation is needed to reveal the biological
mechanisms behind the improvements seen.

Other Duke members of the team were Andrew Sherwood, Ph.D.,
Michael Babyak, Ph.D., Lana Watkins, Ph.D., Robert Waugh, M.D.,
Anastasia Georgiades, Ph.D., Simon Bacon, Ph.D., and Edward
Coleman. Other members were Alan Hinderliter, M.D., University
of North Carolina-Chapel Hill and Junichiro Hayano, M.D.,
Nagoya City University Hospital, Nagoya, Japan.

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