Practicing yoga for at least three hours a week for three months reduced the fatigue and inflammation in breast cancer survivors, compared with survivors who did no yoga, researchers reported.
And the more yoga, the greater the change.
At six months - three months after the formal yoga had ended - fatigue was 57 percent lower in the women who had done yoga, compared with those who had not. Inflamma-tion, measured by blood tests, was reduced by up to 20 percent, said the researchers, from the Ohio State University Compre-hensive Cancer Center.
"We also think the results could easily generalize to other groups of people who have issues with fatigue and inflammation," Janice Kiecolt-Glaser, the lead researcher and a psychiatry and psychology professor at Ohio State, said in a statement.
Two hundred breast cancer survivors were divided into two groups: one that took two 90-minute Hatha yoga classes a week, and one that did no yoga. The yoga practitioners also were encouraged to do additional yoga at home, and did so - an average of almost 25 minutes a day. The women were yoga novices.
The researchers noted that yoga can be tailored to various abilities - the women in the study were ages 27 to 76 - and has been shown to help with mood and sleep among cancer survivors.
The study did not include aerobic exercise, and the participants did not lose weight.
And that, Kiecolt-Glaser said by telephone, led to a surprise. Other research had shown that inflammation - a mechanism for loss of function and disability - was unlikely to be reduced without weight loss. But she said there could be several reasons why her subjects had reduced inflammation without losing weight, including that yoga helps sleep and stress, which are associated with inflammation.
The women practiced Hatha yoga, a restorative form that was recommended by an expert in Columbus, Ohio, Kiecolt-Glaser said.
Breast cancer treatment can be exhausting, and that can lead to less activity, which in turn can lead to a decreased capacity for activity in what Kiecolt-Glaser called "a downward spiral."
"Breast cancer survivors with lower levels of physical activity have a higher risk for premature death," Kiecolt-Glaser and colleagues from Ohio State, including her husband Ronald Glaser, wrote in the Journal of Clinical Oncology. About one-third of survivors say that fatigue interferes with their daily activities.
The people who did not take yoga in the study were offered yoga classes at the end of the study, and Kiecolt-Glaser said 60 percent to 70 percent of them enrolled.