Cancer survivors might want to try yoga to sleep better and have more energy, according to a new study that will be presented at a meeting in early June.

"Physicians and oncologists are often uncomfortable advising patients who want to use therapies that are complementary to standard cancer therapy," Dr. Douglas Blayney, president of the American Society of Clinical Oncology, said in an interview.

"Here we have a studied intervention, one that has been subjected to clinical trials and, lo and behold, it seems to be beneficial," added Blayney, who was not involved in the new research.

For the study, researchers randomly assigned more than 400 cancer survivors to one of two groups. Most had been treated with chemotherapy for breast cancer.

One group did gentle Hatha yoga and restorative yoga -- including special postures and breathing and mindfulness exercises -- twice a week for a month. The other was only monitored, following standard practice.

Those who did yoga were able to cut back on sleeping pills and slept better, as measured by a 22 percent increase in sleep quality on a commonly used scale. That was nearly twice the improvement of survivors who didn't do the exercises.

Yoga also cut fatigue by close to half, and led to a small increase in quality of life.

That is good news for cancer patients, said Karen Mustian of the University of Rochester Medical Center in New York, who led the study. "We really don't have any good remedies for fatigue for cancer survivors," she told Reuters Health.

Although patients may take drugs to help them sleep, such medications have side effects and aren't usually long-lasting. That led Mustian's team to look for alternatives.

How yoga achieves its relaxing effects isn't completely clear.

"It may be promoting social bonding," Mustian said, adding that preliminary studies have suggested it could also lower stress hormones.

For cancer survivors seeking help from yoga, Mustian recommends looking for Yoga Alliance-certified instructors, especially those who have experience with people dealing with illness. She also stressed that the results may not apply to all forms of yoga.

"A physician can say with some confidence," Blayney said, "yes, this kind of yoga program may be useful."

SOURCE: American Society of Clinical Oncology Annual Meeting, June, 2010.