Exercise Program Accelerates Recovery After Chemotherapy
chemotherapy for breast cancer boosted the activity of
infection-fighting T cells in women who worked out regularly, according
to data from a study conducted at Penn State University under the
direction of Andrea Mastro, professor of microbiology and cell biology.
Mastro's findings indicate that exercise can help restore immune
systems damaged by anti-cancer drugs, which destroy healthy as well as
present the research at the "Era of Hope" meeting of the Department of
Defense Breast Cancer Research Program in Philadelphia, Pennsylvania,
on 10 June 2005. The meeting will include presentations by Mastro and
other scientists who are developing a better understanding of the role
of everyday choices people make about activities such as eating and
fitness regimens in causing or preventing disease.
study, women between the ages of 29 and 71 were assigned to an exercise
group of 28 women or a non-exercise group of 21 women. Women in the
exercise group began the exercise routine within a month of completing
post-surgical therapy. All exercisers followed a similar
regimen--stretching to warm up, use of flex-bands for resistance
training, and an aerobic activity of their choice: treadmill, exercise
bike, or walking. In the exercise group, each woman was paired with a
kinesiology intern who served as a personal trainer.
"For the first
three months, the women worked out with the trainers at our clinical
research center three times a week for about 60 to 90 minutes, at a
level the trainers determined was appropriate," Mastro explains. "We
designed an exercise program that could be done without a gym, and for
the second three months, participants had the option of working out at
Most of the
exercisers preferred to continue with the personal trainers at the
research center. Women who chose to work out at home kept an exercise
log, which they discussed with the trainer during telephone interviews
or weekly visits to the Penn State University Park campus. During the
first three months, compliance with the exercise regimen was about 82
percent, dropping to 76 percent during the second three-month period.
According to feedback, distance from the campus was a factor in the
conducted before the intervention, at three months, and at six months.
Measurements for some immune functions improved, with exercisers
showing more activated lymphocytes than non-exercisers. Additionally,
concentrations of an inflammatory substance (IFN-_) that indicates
trauma such as that caused by cancer treatment decreased in the
exercisers but increased in the non-exercisers during the first three
months. Another assay suggested that lymphocytes damaged or killed by
cancer therapy were replaced more quickly in the exercise group with
new and responsive lymphocytes--those that can respond to foreign
substances by dividing to create more invader-fighting cells.
"We know that
chemotherapy-induced decreases in T cells can persist for many years,
and data from the literature suggest that, in the period immediately
following chemotherapy, the surviving T cells may be weakened as well,"
Mastro said. "That's why we're pleased to find evidence that
appropriate exercise can help a breast-cancer survivor's immune system
bounce back after therapy." She noted that, during the recruitment
phase, some women said that their doctors had counseled them not to
exercise after therapy.
test results showed improvements in various physical functions, such as
endurance, upper-body strength (grip strength, biceps, triceps), and
volume of oxygen intake (VO2max). For women who exercised throughout
the program, these measures of physical function were better at six
months than at three months. On a standard questionnaire, exercisers
also scored higher on overall quality of life, social well-being, and
fatigue levels than the non-exercisers.
There were no
differences in results between women who exercised at home or at the
research center. There were no significant differences between the two
groups in education, cancer treatment, or stage, age, overall health,
body mass index, or diet. In both groups, equal numbers of women had
lumpectomy or mastectomy, most of the women had the same chemotherapy
followed by radiation therapy, and most reported doing little if any
regular exercise before diagnosis. Among those who had exercised before
their diagnosis, walking was generally the activity of choice. The
study excluded women who had other serious health conditions or took
drugs that could affect the immune system.
conducted in a similar population by Canadian researchers and published
in the April issue of the Journal of Applied Physiology, also found
that exercisers had a greater percentage of activated T cells. Although
that research was conducted for three months rather than six and
examined aerobic conditioning rather than resistance training, Mastro
considers the two studies to be complementary.
As a follow
up, Mastro hopes to conduct a retrospective study of breast-cancer
survivors to determine whether their immune systems are still depressed
five years after treatment.