There are 25 randomized controlled trials examining the effects of yoga on cancer patients. Most of these studies exclusively enrolled breast cancer patients. The early studies are heterogeneous and have various methodologic shortcomings; however, there have been higher quality studies more recently. Overall, the psychological outcomes in these studies are very consistent, beneficial, and have large effect sizes. Physical outcomes are less consistent and demonstrate smaller effect sizes. Fatigue in particular has been studied in multiple randomized controlled trials, and a systematic review concluded: “Yoga may be beneficial for reducing cancer-related fatigue in women with breast cancer; however, conclusions should be interpreted with caution as a result of bias and inconsistent methods used across studies." Low-intensity forms of yoga, specifically gentle hatha and restorative, are feasible, safe, and effective for treating sleep disruption, cancer-related fatigue, cognitive impairment, psychosocial distress, and musculoskeletal symptoms in cancer patients receiving chemotherapy and radiation as well as cancer survivors.
A unique 2017 pilot study examined the effects of a patient-caregiver dyadic yoga program for high-grade glioma patients who were undergoing radiation therapy and their family caregivers; it found significant improvements in patients' sleep disturbance as well as quality of life for both patients and caregivers.
A recent systematic review and meta-analysis found that yoga had a modest but clinically relevant reduction in blood pressure (systolic blood pressure: −4.59 mm Hg; diastolic blood pressure: −3.65 mm Hg). Yoga has been consistently superior to no treatment but has not been clearly superior to aerobic exercise.
A 2017 Cochrane review of 12 trials involving 1080 patients with chronic low back pain concluded that there is low to moderate certainty evidence that yoga results in small to moderate improvements in function at 3 and 6 months, but it was not shown whether yoga was superior to other exercises for back pain. A previous systematic review and meta-analysis concluded that there was strong evidence for short-term benefit on pain, long-term benefit on pain, reduced back-specific disability, and increased global improvement and moderate evidence for a long-term benefit on back-specific disability. Furthermore, an additional randomized controlled trial concluded that a 6-week yoga intervention is a cost-effective early treatment for low back pain. No serious adverse events occurred in any of these studies. Lastly, a 2017 randomized controlled study of 320 patients with nonspecific low back pain found that yoga was noninferior to physical therapy with regard to disability and pain.
D. Chronic Obstructive Pulmonary Disease (COPD)
A systematic review and meta-analysis of 10 randomized controlled trials of more than 500 COPD patients found that yoga training significantly improved forced expiratory volume in 1 second (FEV1), 6-minute walking distance, and quality of life measures. However, yoga training had no significant effects on forced vital capacity (FVC), FEV1/FVC, and FEV1 predicted value. In a 2016 randomized controlled trial of 81 coal miners with COPD, yoga significantly reduced dyspnea and fatigue and improved measured oxygen saturation.
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et al. Blood pressure response to meditation and yoga: a systematic review and meta-analysis. J Altern Complement Med. 2017 Sep;23(9):685–95.
et al. Physical therapy, or education for chronic low back pain: a randomized noninferiority trial. Ann Intern Med. 2017 Jul 18;167(2):85–94.
et al. Yoga treatment for chronic non-specific low back pain. Cochrane Database Syst Rev. 2017 Jan 12;1:CD010671.