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Contact: amurphy@acc.org;
202-375-6476
June 14, 2007
Aerobic Exercise is Best Fitness Program
for Patients With Stable Heart Failure
Walking and bicycle riding improve heart’s size and
pumping ability
Countless exercise programs claim to trim the thighs, abs
and buttocks, but how many offer to reshape a flabby heart?
According to new research, aerobic exercise does just that
for patients with stable heart failure, literally turning
an enlarged heart into a trimmer,
Countless exercise programs claim to trim the
thighs, abs and buttocks, but how many offer to reshape a
flabby heart? According to new research, aerobic exercise
does just that for patients with stable heart failure, literally
turning an enlarged heart into a trimmer, more efficient organ
for pumping blood throughout the body.
The research, published in the June 19, 2007, issue of the
Journal of the American College of Cardiology (JACC), comes
with a coda, however: It may be best to focus on aerobics
and leave the weight lifting to someone else.
The study showed that when patients with heart failure did
aerobic exercise several times a week, the oversized heart
became significantly smaller and better able to pump blood.
Researchers were surprised to find that those who added weight
lifting to the exercise routine to enhance muscle strength
did not enjoy a similar improvement in the heart’s size
or function.
“If I were to choose a type of exercise training for
a patient with heart failure, I’d choose aerobic exercise,”
said Mark J. Haykowsky, Ph.D., an associate professor of rehabilitation
medicine at the University of Alberta in Edmonton, Alberta,
Canada. “It’s aerobic training that provides the
greatest benefit.”
An estimated 5.2 million people in the United States have
heart failure, a condition that accounts for more than a million
hospitalizations each year. The total direct and indirect
costs linked to heart failure exceed $33 billion annually.
In most cases, heart failure is the result of years of high
blood pressure or damage from a heart attack. Over time, the
heart becomes enlarged, misshapen, and too weak to effectively
pump blood, a process known as remodeling. As a result, patients
typically become short of breath even with very little activity.
For many years, doctors recommended that people with heart
failure avoid exercise. In some cases, patients were even
put on bed rest in an attempt to relieve the heart of any
extra stress. Over the last decade, however, it has become
increasingly clear that exercise is good for patients with
heart failure, not only reducing symptoms and allowing patients
to live more active lives, but also reversing some of the
harmful hormonal changes that take place as the body attempts
to compensate for a weakened heart.
Previous studies have reported conflicting results on the
effect of exercise on the heart’s size and function,
however. “We knew that exercise could improve fitness
and exercise capacity by about 15 percent, and that exercise
could make muscles stronger and larger. But we didn’t
know the effects of exercise training on ventricular remodeling,”
Dr. Haykowsky said.
For the study Dr. Haykowsky and his colleagues analyzed data
from 14 separate randomized trials involving a total of 812
patients with heart failure. The trials each quantified the
effects of exercise by measuring changes in ejection fraction,
the percent of blood pumped from the left ventricle to the
blood vessels with each beat of the heart. About half of the
studies also measured the heart’s size, both at the
end of diastole, the part of the cardiac cycle when the heart
is relaxed and filling with blood, and at the end of systole,
when the heart is squeezing and forcing blood out into the
circulation.
In nine studies, patients did aerobic exercise—walking
or bicycling, for example—for 20 to 60 minutes approximately
3 times a week, at an intensity equal to 60 percent to 80
percent of their peak ability. In four studies, patients supplemented
aerobic exercise with strength training, and in one study,
patients did only strength training. Study participants were
clinically stable but had markedly abnormal heart function,
with an average ejection fraction of just 23 percent. (A normal
ejection fraction is 50 percent or greater.)
The analysis showed that ejection fraction improved significantly
in patients who did aerobic training (2.59 percent, on average).
Similarly, the patients’ enlarged hearts became significantly
smaller, with a reduction in both end-diastolic volume (11.49
mL, on average) and end-systolic volume (12.87 mL). By comparison,
patients who combined aerobic exercise with strength training
showed no significant improvements in ejection fraction or
the size of the heart. The single study that evaluated strength
training alone showed a drop in ejection fraction, but it
was not statistically significant; the study did not measure
changes in the size of the heart.
Dr. Haykowsky speculated that weight lifting and other forms
of strength training may not have shown the benefits of aerobic
training in reshaping the heart because strength training
results in a heightened pressure load, which may actually
increase the stress on the heart.
The importance of the new study is that it provides guidance
in designing an exercise program for patients with heart failure,
according to Stanley A. Rubin, M.D., F.A.C.C., chief of inpatient
cardiology and a professor of medicine at the Veterans Affairs-UCLA
Medical Program in Los Angeles.
“This study clarifies for heart failure patients and
for their doctors the best form of exercise training,”
said Dr. Rubin, who wrote an accompanying editorial in the
June 19 issue of JACC. “But it’s not a bed of
roses. The patient needs to be motivated, have realistic expectations
of the small but real benefit of exercise and, in particular,
understand that this form of treatment must be accompanied
by extensive dietary, lifestyle and, especially, medication
and device treatments tailored to meet their needs. It’s
not a substitute.”
Dr. Rubin added that patients with heart failure should not
initiate exercise training on their own. To be safe, they
should first be evaluated by a cardiologist and monitored
during exercise, at least initially. Finding a way to pay
for supervised exercise training is a challenge, however,
as Medicare and most private insurance carriers approve payment
for cardiac rehabilitation only if the patient has recently
experienced a heart attack.
There may soon be new evidence on the benefits of exercise
in patients with heart failure. A National Heart, Lung, and
Blood Institute study, HF-ACTION—short for Heart Failure:
A Controlled Trial Investigating Outcomes of Exercise Training—is
recruiting patients at medical centers around the country.
“If this study proves that training not only improves
the exercise capability of patients, but also extends their
life and reduces hospitalizations, insurance payers are likely
to support this as an important addition to an increasingly
potent array of treatments for heart failure,” Dr. Rubin
said.
Dr. Haykowsky reports no potential conflicts of interest
regarding this topic.
The American College of Cardiology is leading the way to
optimal cardiovascular care and disease prevention. The College
is a 34,000-member nonprofit medical society and bestows the
credential Fellow of the American College of Cardiology upon
physicians who meet its stringent qualifications. The College
is a leader in the formulation of health policy, standards
and guidelines, and is a staunch supporter of cardiovascular
research. The ACC provides professional education and operates
national registries for the measurement and improvement of
quality care. More information about the association is available
online at www.acc.org .
The American College of Cardiology (ACC) provides these news
reports of clinical studies published in the Journal of the
American College of Cardiology as a service to physicians,
the media, the public and other interested parties. However,
statements or opinions expressed in these reports reflect
the view of the author(s) and do not represent official policy
of the ACC unless stated so.
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