Researchers from the University of Pennsylvania who collected data from men who attended yoga class twice a week during prostate cancer radiation treatment found that they were less fatigued and had better sexual and urinary function.

In the study, published in the International Journal of Radiation Oncology, Biology, and Physics, patients in the trial received external beam radiation therapy for prostate cancer between six to nine weeks. Patients were put at random into two groups—one participating in a yoga class that met twice a week and the other that served as the control group. Any patient who already practiced yoga on their own, had a history of prior radiation therapy or those with metastatic disease were not eligible for the study. 

Patients filled out a nine-item questionnaire assessing fatigue severity and impact on daily life between two to three weeks before the start of radiotherapy, twice while receiving radiotherapy and a final survey was given within a week of their last yoga class or radiation treatment. 

"At their baseline, before patients started treatment, patients in both groups were on the lower end of the scale, meaning they reported lower amounts of fatigue," said the trial's principal investigator Neha Vapiwala, MD, an associate professor of radiation oncology at Penn, in a statement. "But as treatment went on, we observed a difference in the two groups."

Patients reported they had less fatigue as they attended more yoga sessions, compared to when they began taking classes. However, the other group of patients who did not practice yoga reported that their fatigue increased as treatment progressed. 

Researchers also evaluated the sexual health of both groups. The study utilized the International Index of Erectile Function (IIEF) questionnaire using scores from zero to 25. Scores higher than 21 are considered normal, while scores below 12 are considered moderate to severe erectile dysfunction. Both groups started off with scores of about 11. The yoga group's score hardly changed, while the non-yoga group reported a decline over the course of treatment. 

"Yoga is known to strengthen pelvic floor muscles, which is one of several postulated theories that may explain why this group did not demonstrate declining scores, as seen in the control group," Vapiwala said. "That may also explain the yoga patients' improved urinary function scores, another finding of this trial."