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DURHAM, N.C. - After demonstrating that 30 minutes of brisk
exercise three times a week is just as effective as drug
therapy in relieving the symptoms of major depression in the
short term, Duke University Medical Center researchers have now
shown that continued exercise greatly reduces the chances of
the depression returning.

Last year, the Duke researchers reported on their study of
156 older patients diagnosed with major depression which, to
their surprise, found that after 16 weeks, patients who
exercised showed statistically significant and comparable
improvement relative to those who took anti-depression
medication, or those who took the medication and exercised.

The new study, which followed the same participants for an
additional six months, found that patients who continued to
exercise after completing the initial trial were much less
likely to see their depression return than the other patients.
Only 8 percent of patients in the exercise group had their
depression return, while 38 percent of the drug-only group and
31 percent of the exercise-plus-drug group relapsed.

"The important conclusion is that the effectiveness of
exercise seems to persist over time, and that patients who
respond well to exercise and maintain their exercise have a
much smaller risk of relapsing," said lead researcher, Duke
psychologist James Blumenthal, who published the results of his
team's study in the October issue of the journal Psychosomatic Medicine.

The research was supported by grants from the National
Institutes of Health (NIH). The Duke researchers are now using
a new $3 million NIH grant to better understand the subtle
factors that may explain the positive effects of exercise in a
new trial that begins enrolling patients this month.

"We found that there was an inverse relationship between
exercise and the risk of relapsing - the more one exercised,
the less likely one would see their depressive symptoms
return," Blumenthal explained. "For each 50-minute increment of
exercise, there was an accompanying 50 percent reduction in
relapse risk.

"Findings from these studies indicate that a modest exercise
program is an effective and robust treatment for patients with
major depression," he continued. "And if these motivated
patients continue with their exercise, they have a much better
chance of not seeing their depression return."

Researchers were surprised that the group of patients who
took the medication and exercised did not respond as well as
those who only exercised.

"We had assumed that exercise and medication together would
have had an additive effect, but this turned out not to be the
case," Blumenthal said. "While we don't know the reasons for
this, some of the participants were disappointed when they
found out they were randomized to the exercise and medication
group. To some extent, this 'anti-medication' sentiment may
have played a role by making patients less excited or enthused
about their combined exercise and medication program."

He suggested that exercise may be beneficial because
patients are actually taking an active role in trying to get
better.

"Simply taking a pill is very passive," he said. "Patients
who exercised may have felt a greater sense of mastery over
their condition and gained a greater sense of accomplishment.
They may have felt more self-confident and competent because
they were able to do it themselves, and attributed their
improvement to their ability to exercise."

Once patients start feeling better, they tend to exercise
more, which makes them feel even better, Blumenthal said. The
greatest risk for these patients, since they are older, would
be to suffer an injury or illness that would interrupt their
exercise routine, he added.

While the researchers enrolled middle-aged and elderly
people in their study, Blumenthal said it is logical to assume
that the results would hold true for the general population,
since older people tend to have additional medical problems or
infirmities that might make regular exercise more difficult
than for younger patients.

Researchers used the anti-depressant sertraline (trade name
Zoloft), which is a member of a class of commonly used
anti-depressants known as selective serotonin reuptake
inhibitors (SSRI).

Blumenthal cautioned that the study did not include patients
who were acutely suicidal or had what is termed psychotic
depression. Also, since patients were recruited by
advertisements, these patients were motivated to get better and
interested in exercise.

The research team included, from Duke, Michael Babyak, Steve
Herman, Parinda Khatri, Dr. Murali Doraiswamy, Kathleen Moore,
Teri Baldewicz and Dr. Ranga Krishnan. Edward Craighead, from
the University of Colorado at Boulder also participated.