e4-11: Yoga

According to the National Center for Complementary and Integrative Health, yoga is a mind-body practice with origins in ancient Indian philosophy. The various styles of yoga typically combine physical postures, breathing techniques, and meditation or relaxation. There are numerous schools of yoga in the United States and around the world. Hatha yoga emphasizes postures (asanas) and breathing exercises (pranayama). Some of the famous styles of hatha yoga are Iyengar, Ashtanga, Viniyasa, and Kundalini.

According to the 2017 NHIS survey data, the percentage of adults who practice yoga in the United States has increased substantially, from 9.5% in 2012 to 14.3% in 2017.

There are many yoga teacher training programs in existence. To standardize yoga teacher training in the United States, the nonprofit Yoga Alliance provides a set of educational standards for yoga schools. A teacher trained through a Yoga Alliance-certified school has RYT (Registered Yoga Teacher) after their name according to the following hierarchy:

1. RYT 200 (this is the minimum level of teacher training signifying that the teacher graduated from a Yoga Alliance-approved 200-hour training).

2. RYT 500 (this level signifies graduating from a 500-hour training plus having 100 hours of teaching experience).

3. E-RYT 200 (“E” stands for “experienced.” This designation level means the teacher has 1000 hours of teaching experience and has taught for at least 2 years).

4. E-RYT 500 (this level indicates 2000 hours of teaching experience and that the teacher has taught for at least 5 years).

There are also two specialty designations, RCYT (Registered Children's Yoga Teacher) and RPYT (Registered Prenatal Yoga Teacher), with specific training requirements. All RYTs must complete continuing education hours every 3 years.

As there are many different styles of yoga, when referring patients to a yoga program, keywords that suggest the yoga class may be safe and gentle for medical/surgical patients are “restorative yoga,” “therapeutic yoga,” and “gentle yoga.” Other styles can also be appropriate but are more teacher-dependent. The term “hatha yoga” is non-descript. “Hatha” is a classic yoga term denoting the postures (“asanas”) that are a central element of most yoga practice. When referring patients to a program identified as “hatha yoga,” often the connotation of “hatha” is that the class is classic, appropriate for beginners, and not too strenuous; however, this should be verified before participation.

Like any physical activity, there is a risk of injury with yoga practice. There is no comprehensive study assessing the detailed risks of practicing yoga, but strains, injuries to the trunk, and injuries in older participants appear to be most common. The most common type of adverse event was musculoskeletal (mostly minor sprains and strains), followed next by neurologic (mostly transient paresthesias and headache). The headstand posture caused the most reported injuries (10), followed by the shoulder stand (3) and lotus position (3).

A. Cancer

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.

B. Hypertension

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.

C. Low Back Pain

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.