Source:

http://www.medicinenet.com/script/main/art.asp?articlekey=85093

Regular Exercise Helps Fight Heart Failure

By Amanda Gardner
HealthDay Reporter

WEDNESDAY, Nov. 7 [2007 apparently] (HealthDay News) -- Exercise
boosts the number of progenitor cells in people with heart failure,
and those cells in turn repair and rebuild weakened muscle and blood
vessels, researchers report.

According to two studies that were to be presented Wednesday at the
American Heart Association annual meeting in Orlando, Fla., that
response can dramatically enhance patients' ability to move and work
out.

"Both studies point to the beneficial effect of exercise on patients
with heart failure," said Dr. Sidney Smith, past president of the
American Heart Association and director of the Center for
Cardiovascular Science and Medicine at the University of North
Carolina School of Medicine.

"These observations provide some understanding into the mechanisms
which [make exercise helpful]," Smith said.

More than 5 million people in the United States have heart failure, a
condition that affects the heart's ability to pump blood throughout
the body.

However, researchers are beginning to understand that heart failure
woes come not only from this pumping disorder but from changes in the
legs and other parts of the body.

"The muscle of the leg starts to shrink, so there is less muscle
mass," explained Dr. Axel Linke, a co-author on both studies and
assistant professor of medicine at the University of Leipzig in
Germany. "The endothelium and the vessels supplying blood to the
muscles deteriorate, so they are less flexible, elasticity is
reduced," he said. The endothelium is a layer of cells that lines
blood vessels.

However, exercise opens up the vessels and improves their flexibility
and elasticity.

In the first study, investigators looked at whether exercise training
could activate progenitor cells -- immature cells that can divide into
other cells and help repair tissue.

Fifty men with moderate-to-severe heart failure were randomized to
receive either six months of exercise training under the supervision
of a physician, or to be sent to a control group that remained
inactive.

Exercise consisted of riding a stationary bicycle at least 30 minutes
a day (usually in two sessions).

At the end of six months, biopsies of the patients' thigh quadriceps
revealed that the number of progenitor cells in the exercise group
increased by 109 percent, progenitor cells turning into muscle cells
increased by 166 percent, and progenitor cells actively dividing to
form new cells and repair damage to the muscle increased sixfold.

For the second study, 37 men with severe heart failure were randomly
assigned to receive three months of exercise or to remain inactive.

The exercisers experienced dramatic changes: Circulating progenitor
cells increased 47 percent, progenitor cells beginning to mature into
endothelial cells increased almost 200 percent, and the density of
capillaries in skeletal tissue increased 17 percent. There were no
changes in the control group.

When they began, the exercising patients had peak oxygen uptake in the
range of other patients needing heart transplants. But regular
exercise was linked to an average 35 percent increase in exercise
capacity, giving the men about 75 percent of the capacity seen in
healthy people of the same age.

"Your heart is like an engine with six cylinders, and when we started
the exercise program in those patients, about 3.5 cylinders were just
not working," Linke explained. "After three to six months of exercise
training, two of the cylinders started working again."

"It's a tremendous improvement, and no medication is able to do it,"
he noted.

But patients with heart failure should only embark on an exercise
regimen under the supervision of a physician, Linke added.

"We recommend exercise once a day for up to 20 minutes five days a
week for patients with heart failure, but clearly an exercise program
should be initiated in in-hospital conditions or an outpatient
setting, because you never know how an individual patient might react
to initiation of a training program," he explained.

SOURCES: Axel Linke, M.D., assistant professor, medicine, University
of Leipzig, Germany; Sidney Smith, M.D., past president, American
Heart Association, and director, Center for Cardiovascular Science and
Medicine, University of North Carolina School of Medicine, Chapel
Hill; Nov. 7, 2007, presentations, American Heart Association annual
meeting, Orlando, Fla.

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