NEW YORK (Reuters Health) - Participating in regular group exercise classes can help women with early breast cancer feel better, both physically and mentally, while they're undergoing treatment, according to a study in the British Medical Journal.

"Women being treated for early stage breast cancer should try to accumulate 30 minutes of moderate intensity physical activity 3 to 5 days a week," Dr. Anna Campbell, who led the study, told Reuters Health.

Campbell, at Strathclyde University in Glasgow, Scotland, and her colleagues recruited 203 women undergoing chemo or radiation therapy for breast cancer for the study. The participants, who were free of heart or breathing problems and did not exercise regularly, were randomly assigned to usual care plus a 12-week supervised group exercise program or usual care alone.

The women in the exercise group were encouraged to attend two 45-minute classes led by a trained exercise specialist each week and perform similar exercises on their own once per week at home.

After 12 weeks, women in the exercise group enjoyed improved physical functioning and psychological well being, the authors report. For example, compared to the usual-care group, the exercisers were able to walk greater distances, had greater shoulder mobility, and had a more positive outlook.

There was also a trend toward reduced fatigue and depression in the exercisers and the perception that their overall quality of life had improved.

Six months after the start of the program, 177 of the women completed an evaluation. "At the six months follow-up most of these positive effects were still maintained," Campbell said, and the women in the exercise group also reported fewer nights in hospital and fewer visits to their doctor than those in the comparison group.

"The benefits of the exercise classes are probably caused by a combination of the exercise and the group experience," Campbell said. Importantly, there were no ill effects of exercise in the women.

Doctors "should encourage physical activity for patients with cancer to help combat some treatment-related side effects," Campbell concluded, and "policy makers should consider including opportunities for exercise as part of a cancer-care package, similar to the exercise component in cardiac rehabilitation."