Derry, H.M., Jaremka, L.M., Bennett, J.M., Peng, J., Andridge, R., Shapiro, C., . . . Kiecolt-Glaser, J.K. (2014). Yoga and self-reported cognitive problems in breast cancer survivors: A randomized controlled trial. Psycho-Oncology. Advance online publication.
To determine the effects of yoga on self-reported cognitive function
Certified yoga instructors led two 90-minute yoga group classes per week for 12 weeks. Each group contained 4–20 participants. Hatha yoga poses targeting relaxation, mindful breathing, chest opening, spinal extension, upper-body strength, and mobility were predetermined for each of the 24 sessions, and protocol drift was monitored. Pamphlets describing the poses from the classes and a yoga DVD were provided for home practice. Participants recorded weekly home and class time to determine dose effects. Participants who missed a class were called to improve adherence. Waitlist control participants continued regular activities and were directed not to begin yoga practice until after their final assessments. Measures were assessed before the behavioral intervention, immediately after the 12-week intervention, and three months after the intervention.
Randomized, waitlist-controlled trial
At baseline, the average self-reported cognitive impairment was slight to moderate and did not differ between groups. Overall group and group-by-time effects were found (p < .05, both). Although no differences were found immediately after the 12-week intervention, the intervention group reported significantly less cognitive impairment than controls three months after the intervention ended (p < .01). However, these effects did not remain after controlling for symptom covariates (e.g., anxiety, depression, fatigue, sleep quality). Participants with more daily yoga practice (mean of 29 minutes) reported less cognitive impairment postintervention through three months (p = .011), and participants with less daily yoga practice (mean of 18 minutes) or no daily yoga practice did not report these changes. This dose response remained when controlling for symptom covariates. At three months, the intervention group reported more physical activity than controls (p = .032). Cytokine levels did not predict changes in self-reported cognitive impairment.
A 12-week, group Hatha yoga intervention provided by a trained instructor may improve self-reported cognitive impairment in breast cancer survivors. This effect may be mediated by improvements in co-occurring symptoms. Practicing yoga for at least 30 minutes per day may be required for a significant improvement over time in cognitive impairment.
A group Hatha yoga class delivered by a trained facilitator may improve cognitive impairment for breast cancer survivors. However, more research with a longer follow-up period is warranted to determine whether the intervention is effective, what component of the intervention is active, and whether yoga is practical for implementation in practice.