The study, “Randomized trial of Tibetan yoga in patients with breast cancer undergoing chemotherapy,” appeared in the journal Cancer.
Sleep disruption and fatigue are two of the most common and debilitating adverse effects of chemotherapy in cancer patients, observed the study’s senior author, Lorenzo Cohen. He is a professor of Palliative, Rehabilitation, and Integrative Medicine at the cancer center, and director of its Integrative Medicine Program.
Excessive drowsiness is also frequent in these patients.
“Previous research has established that yoga effectively reduces sleep disturbances for cancer patients, but have not included active control groups or long-term follow-up,” Cohen said in a press release. “This study hoped to address previous study limitations.”
The research covered 227 women with stage I-III breast cancer — invasive, but limited to the breast and lymph nodes — who were having chemotherapy at the MD Anderson Cancer Center.
Patients were randomized to take Tibetan yoga, to do stretching, or to receive the usual care. Those involved in the Tibetan yoga and stretching programs attended four 75- to 90-minute-long classes during chemotherapy, followed by three booster sessions over the next six months.
Patients in the yoga program had one-on-one sessions with a trainer. They practiced mindfulness, focused attention, controlled breathing, meditation, and gentle movements combined with breathing patterns. Patients were encouraged to do yoga at home daily.
Before starting, the patients filled out questionnaires and had their sleep quality assessed 24 hours a day for seven days with an actigraphy watch, which measures rest and activity cycles. Patients had follow-up assessments a week after the end of their program, and three, six, and 12 months later. Sleep disturbances and fatigue were assessed with self-reporting.
Scientists said those who practiced Tibetan yoga at least two times a week reported fewer daytime problems a week after treatment than women practicing less often and those receiving usual care. The same was true with improved sleep quality and sleep efficiency — or the time spent asleep compared with total time in bed.
Researchers also saw long-term sleep improvements in the same patients. Compared with women who practiced yoga less often, patients practicing it at least two times a week reported decreased daily sleep-related disturbances three months after treatment, and better sleep quality and efficiency at six months. The same was true when the twice-a-week yoga group was compared with the usual care group.
Importantly, the results also showed that “women who practiced yoga outside of class had improved sleep outcomes over time,” Cohen said.
One of the study’s limitations was the difficulty of recruiting patients taking chemotherapy, which yielded a low participation rate of 56 percent. Other limitations included a high patient drop-out rate, a relatively homogeneous patient population, and the limited time of the yoga instructor-patient encounter.
Future research should use shorter in-class yoga instruction and increased patient engagement in practices outside classes, the researchers said.