THURSDAY, Sept. 6, 2007 (HealthDay News) -- Exercise may be the last thing breast cancer patients want to do, especially if they're fatigued. But workouts can improve quality of life, boost self-esteem during a difficult time, and even help women get through their chemotherapy treatments on schedule, two new studies find.
Previously, numerous studies had found that exercise can help prevent cancers. "A newer area is looking at it on the post-diagnosis side," said Kerry Courneya, a professor and Canada research chair in physical activity and cancer at the University of Alberta in Edmonton.
Courneya led one of the new studies, in which he found that regular exercise helped women who survived early-stage breast cancer to improve muscle strength, self-esteem, body mass, fitness, and reduce their body fat.
He recruited 242 women with breast cancer, average age 49, who were beginning their chemotherapy regimen. They were assigned to one of three groups: 82 to a resistance-training exercise group, 78 to an aerobic exercise group and the other 82 to "usual care," in which they were asked not to initiate an exercise program but were offered a program after the study ended.
The exercise groups worked out under supervision for one hour three times a week for 17 weeks. "They did this while undergoing chemotherapy," Courneya said.
"Our concern initially was that exercise might interfere with their ability to complete the treatment," Courneya said. "The concern among nurses and doctors was that patients would be too drained" after workouts.
The opposite turned out to be true. "The most novel finding we had was, those who did the weight [resistance] training actually increased their ability to complete chemotherapy on time," he said. "It was an unexpected finding."
Courneya said 78 percent of those in the resistance group finished 85 percent or more of their recommended chemotherapy doses, as did 74.4 percent of those in the aerobic exercise group, compared to just 65.9 percent in the usual care group.
Exactly why the exercisers were better at chemotherapy compliance isn't known, but Courneya said workouts may boost white blood cell counts. "If white blood cell counts fall during chemo, the chemotherapy sometimes has to be delayed or the amount of drug given reduced," he explained.
Both exercise groups also reported improvements in their self-esteem. "And that can be an important issue while undergoing chemotherapy because of hair loss and other concerns," Courneya said.
There were other benefits to exercise. "In the aerobic group, we prevented fitness declines. The resistance group increased strength. The aerobic exercise group prevented fat gain. The usual care group gained two pounds of fat and no muscle. The aerobic group did not put on fat. The resistance group added two pounds of lean body mass," he said.
Yoga provides benefits, too, according to Alyson B. Moadel, an assistant professor of epidemiology and population health at Albert Einstein College of Medicine in New York City, who led the second study. Her team compared several quality-of-life measures among 84 women with early stage breast cancer who participated in yoga classes weekly for 12 weeks. They were measured against 44 women who didn't do yoga. About half of the women underwent chemotherapy or radiation treatment during the study period, while the others either had finished those treatments or did not need them.
The researchers found that yoga had pronounced benefits for those not receiving chemotherapy. "A once-per-week, gentle-seated yoga program can have significant benefits for breast cancer survivors who are not on chemotherapy, in the areas of emotional well-being and mood, and overall quality of life," she said.
Moadel speculated that those receiving chemotherapy may need more intense yoga to reap the benefits.
"Other studies have found that yoga is associated with improved mood and overall quality of life in patients with cancer," she said. "Our study is the first to examine yoga with an ethnically diverse population, the majority of whom were African-American and Hispanic."
Both studies were published online Sept. 4 in the Journal of Clinical Oncology.
Cheryl Rock, a professor of nutrition at the University of California, San Diego, School of Medicine, said the new research makes sense. "The biggest problem is convincing people to ignore that voice that says, 'I am too tired to exercise.'"
"It's very counter-intuitive," she said of the findings. "There is a huge amount of medical literature on the general population linking exercise with improved mood," she said. And exercise can especially help cancer patients going through chemotherapy. "Chemo is not only physically stressful but psychologically stressful," she said.
Cancer patients considering exercise should talk to their doctor first, she said.
To learn more about exercise during cancer treatment, visit the American Cancer Society.