Different dictionaries offer two viewpoints of yoga:
1) It is a type of exercise in which the body moves into various positions in order to become more fit or flexible, to improve the breathing, and to relax the mind.
2) It is a philosophy.

On December 1, 2016, yoga was listed by UNESCO as an intangible cultural heritage.

In health care, yoga often serves as a complementary mind-body practice; it is increasingly being incorporated into cancer care. It can be done in one’s home via DVD or web-based programs, or via group practices led by instructors.
Evidence-based studies tend to use a few yoga styles that incorporate specific physical postures, breathing practices, and meditation. Most studies do not investigate a specific yoga style to target a specific symptom, but rather a blend of the three styles described below. Of note, while the definitions of different yoga styles can be considered standard, the classes or instruction is not, which is a limitation in the evidence underlying most physical exercise regimens.
Hatha yoga is a type of yoga known for its practice of body postures, which give the muscles firmness and elasticity. It is characterized by a smooth transition between one posture and the next. Classes are slow-paced and designed for beginners.
Yoga Iyengar represents a common modern Hatha yoga system that emphasizes proper alignment of the body into postures via supports (blocks, straps, and bolsters).
Restorative yoga aims to undo chronic stress through conscious relaxation. Classes involve guided meditations and long holds of seated or supine postures, with the body fully supported by props.

Cancer-related fatigue (CRF)
It is distinct from other common forms of fatigue (e.g., overexertion, lack of sleep, anemia) in that it does not improve with rest, significantly limits activities of daily living, may stay for years, and is often more difficult to treat.
• Some trials showed significant improvement in patient-reported CRF at 1-, 3-, and 6-month follow-ups when yoga was practiced at low to moderate intensity, 60- to 120-minute sessions, 1-3 x week, over 4-12 weeks.
• Two trials compared yoga to conventional strengthening exercises for early-stage breast cancer patients and survivors. Both interventions were found to significantly improve patient reported CRF; no significant differences were found between the two interventions.
• A study in patients with metastatic breast cancer showed moderate improvement in patient-reported CRF at post-intervention (8 weeks) and 6- month follow-up compared to a social support group intervention.

Sleep disruption
Several trials showed significant improvement in sleep disruption, improved subjective sleep quality, faster sleep latency, longer sleep duration, and less use of sleep medications when practiced at low to moderate intensity, 60- to 120-minute sessions, 1-3 x week, over 4-10 weeks.

Cognitive impairment
Two randomized clinical trials showed post-intervention improvement in concentration, distraction, and memory when practiced at low to moderate intensity, 75- to 90-minute sessions, 2 x week, over 4-12 weeks.

Psychological distress
• Several trials showed improvement in patient-reported anxiety, depression, and psychological distress when practiced at low to moderate intensity, 60- to 90-minute sessions, 1-7 x week, over 3-12 weeks.
• A study in patients with metastatic breast cancer showed improvement at 8 weeks and 3- and 6-month follow-ups for patient-reported anxiety and depression.

Musculoskeletal pain
Only one trial in breast cancer patients on aromatase inhibitors showed a significant reduction in musculoskeletal pain, muscle aches, and general discomfort when practiced at low to moderate intensity, 75-minute sessions, 2 x week, over 4 weeks.

See reference for more information.

Adapted from Lewis J. Yoga for cancer-related symptoms. Palliative Care Network of Wisconsin. Fast facts and concepts #391. Internet. Accessed on February 2, 2020