Unsolved:Yoga for therapeutic purposes

Yoga for therapeutic purposes is the use of yoga as exercise, consisting mainly of postures called asanas, as a gentle form of exercise and relaxation applied specifically to improve health. This form of yoga is widely practised in classes, and may involve meditation, imagery, breath work (pranayama) and music.

At least three types of health claim have been made for yoga: magical claims for medieval haṭha yoga, including the power of healing; unsupported claims of benefits to organ systems from the practice of asanas; and claims of specific medical and psychological benefits from studies of differing sizes using a wide variety of methodologies.

Systematic reviews have found beneficial effects of yoga on low back pain and depression, but despite much investigation little or no evidence for benefit in specific medical conditions. Study of trauma-sensitive yoga has been hampered by weak methodology.

Context

Different schools teach yoga with emphasis on aerobic exercise (such as Bikram Yoga), precision in the asanas (like Iyengar Yoga), or spirituality (like Sivananda Yoga). Unbranded "hatha yoga" (not to be confused with medieval haṭha yoga) may teach any combination of these.

Yoga classes used as therapy usually consist of asanas (postures used for stretching), pranayama (breathing exercises), and relaxation in savasana (lying down). The physical asanas of modern yoga are related to medieval haṭha yoga tradition, but they were not widely practiced in India before the early 20th century.

The number of schools and styles of yoga in the Western world has grown rapidly from the late 20th century. By 2012, there were at least 19 widespread styles from Ashtanga Vinyasa Yoga to Viniyoga. These emphasise different aspects including aerobic exercise, precision in the asanas, and spirituality in the haṭha yoga tradition. These aspects can be illustrated by schools with distinctive styles. Thus, Bikram Yoga has an aerobic exercise style with rooms heated to 105 °F (41 °C) and a fixed pattern of 2 breathing exercises and 26 asanas. Iyengar Yoga emphasises correct alignment in the postures, working slowly, if necessary with props, and ending with relaxation. Sivananda Yoga focuses more on spiritual practice, with 12 basic poses, chanting in Sanskrit, pranayama breathing exercises, meditation, and relaxation in each class, and importance is placed on vegetarian diet.

Types of claim

At least three different types of claim of therapeutic benefit have been made for yoga from medieval times onwards, not counting the more general claims of good health made throughout this period: magical powers; biomedical claims for marketing purposes; and specific medical claims supported by evidence.

Magical powers

Medieval authors asserted that Haṭha yoga brought physical (as well as spiritual) benefits, and provided magical powers including of healing. The Hatha Yoga Pradipika (HYP) states that asanas in general, described as the first auxiliary of haṭha yoga, give "steadiness, good health, and lightness of limb." (HYP 1.17) Specific asanas, it claims, bring additional benefits; for example, Matsyendrasana awakens Kundalini and makes the semen steady; (HYP 1.27) Paschimottanasana "stokes up the digestive fire, slims the belly and gives good health"; (HYP 1.29) Shavasana "takes away fatigue and relaxes the mind"; (HYP 1.32) while Padmasana "destroys all diseases" (HYP 1.47). These claims lie within a tradition across all forms of yoga that practitioners can gain supernatural powers. Hemachandra's Yogashastra (1.8–9) lists the magical powers, which include healing and the destruction of poisons.

Biomedical claims for marketing purposes

Styles of yoga differ in their approach to the asanas. Iyengar Yoga emphasises correctness, seen here as a practitioner uses a yoga brick to attain correct alignment in Utthitha Trikonasana.

Twentieth century advocates of some schools of yoga, such as B. K. S. Iyengar, have for various reasons made claims for the effects of yoga on specific organs, without adducing any evidence. The yoga scholar Andrea Jain describes such claims in terms of "elaborating and fortifying his yoga brand" and "mass-marketing", calling Iyengar's 1966 book Light on Yoga "arguably the most significant event in the process of elaborating the brand". The yoga teacher Bernie Gourley notes that the book neither describes contraindications systematically, nor provides evidence for the claimed benefits. Jain suggests that "Its biomedical dialect was attractive to many." For example, in the book, Iyengar claims that the asanas of the Eka Pada Sirsasana cycle

tone up the muscular, nervous and circulatory systems of the entire body. The spine receives a rich supply of blood, which increases the nervous energy in the chakras (the various nerve plexuses situated in the spine), the flywheels in the human body machine. These poses develop the chest and make the breathing fuller and the body firmer; they stop nervous trembling of the body and prevent the diseases which cause it; they also help to eliminate toxins by supplying pure blood to every part of the body and bringing the congested blood back to the heart and lungs for purification.

The history of such claims has been reviewed by William J. Broad in his 2012 book The Science of Yoga. Broad argues that while the health claims for yoga began as Hindu nationalist posturing, it turns out that there is ironically "a wealth of real benefits".

Evidence-based medical claims

Researchers have studied the medical and psychological effects of yoga as exercise in a wide range of trials and observational studies, sometimes with careful controls, providing evidence of differing quality about yoga's possible benefits. The various types of claim, and the evidence for them, are discussed below.

Research

Methodology

Much of the research on the therapeutic use of yoga has been in the form of preliminary studies or clinical trials of low methodological quality, including small sample sizes, inadequate control and blinding, lack of randomization, and high risk of bias.

For example, a 2010 literature review on the use of yoga for depression stated, "although the results from these trials are encouraging, they should be viewed as very preliminary because the trials, as a group, suffered from substantial methodological limitations." A 2015 systematic review on the effect of yoga on mood and the brain recommended that future clinical trials should apply more methodological rigour.

Mechanisms

A yoga class relaxing in Supta Baddha Konasana. There is evidence that yoga relieves stress by multiple mechanisms.

The practice of asanas has been claimed to improve flexibility, strength, and balance; to alleviate stress and anxiety, and to reduce the symptoms of lower back pain, without necessarily demonstrating the precise mechanisms involved. A review of five studies noted that three psychological (positive affect, mindfulness, self-compassion) and four biological mechanisms (posterior hypothalamus, interleukin-6, C-reactive protein and cortisol) that might act on stress had been examined empirically, whereas many other potential mechanisms remained to be studied; four of the mechanisms (positive affect, self-compassion, inhibition of the posterior hypothalamus and salivary cortisol) were found to mediate yoga's effect on stress.

Low back pain

A 2013 systematic review on the use of yoga for low back pain found strong evidence for short- and long-term effects on pain, and moderate evidence for long-term benefit in back-specific disability, with no serious adverse events. Ten randomised controlled trials were analysed, of which eight had a low risk of bias. The review stated that yoga can be recommended as an additional therapy to chronic low back pain patients.

Mental disorders

A 2013 systematic review on the use of yoga for depression found moderate evidence of short-term benefit over "usual care" and limited evidence compared to relaxation and aerobic exercise. Only 3 of 12 randomised controlled trials had a low risk of bias. The diversity of the studies precluded analysis of long-term effects.

A 2015 systematic review on the effect of yoga on mood and the brain concluded that "yoga is associated with better regulation of the sympathetic nervous system and hypothalamic-pituitary-adrenal system, as well as a decrease in depressive and anxious symptoms in a range of populations."

Trauma-sensitive yoga has been developed by David Emerson and others of the Trauma Center at the Justice Resource Institute in Brookline, Massachusetts. The center uses yoga alongside other treatments to support recovery from traumatic episodes and to enable healing from PTSD. Workers including Bessel van der Kolk and Richard Miller have studied how clients can "regain comfort in their bodies, counteract rumination, and improve self-regulation through yoga." A 2018 systematic review of 12 studies, that had individually found positive effects compared to their control groups, was unable to find strong evidence of benefit from yoga for post-traumatic stress disorder, depression, or anxiety following traumatic experiences, and called for more rigorous study design.

Other conditions

There is little reliable evidence that yoga is beneficial for specific medical conditions, and an increasing amount of evidence that it is not. A systematic review found weak evidence for the use of yoga for rheumatic diseases, with no evidence of its safety. Another systematic review found no evidence of benefit in treatment of epilepsy or menopause-related symptoms. Practice of yoga had no effect on the underlying mechanisms of cancer. A systematic review found little evidence that yoga helps people with dementia perform their daily activities. A systematic review showed no effect of yoga on attention deficit hyperactivity disorder. A systematic review concluded that there was not enough evidence to be able to assess the effectiveness of yoga for treating women with urinary incontinence.

Safety

Although relatively safe, yoga is not a risk-free form of exercise. Sensible precautions can usefully be taken – for example the avoidance of advanced moves by beginners, not combining practice with psychoactive drug use, and avoiding competitiveness.

A small percentage of yoga practitioners each year suffer physical injuries analogous to sports injuries. The practice of yoga has been cited as a cause of hyperextension or rotation of the neck, which may be a precipitating factor in cervical artery dissection.

See also

• Exercise is Medicine
• International Journal of Yoga
• International Association of Yoga Therapists
• Neurobiological effects of physical exercise
• Yoga foot drop

Sources

• Broad, William J. (2012). The Science of Yoga: The Risks and the Rewards. Simon and Schuster. ISBN 978-1-4516-4142-4. https://books.google.com/books?id=BGrx76leGtgC. 
• Iyengar, B. K. S. (1979) [1966]. Light on Yoga: Yoga Dipika. Unwin Paperbacks. ISBN 978-1855381667. 
• Jain, Andrea (2015). Selling Yoga : from Counterculture to Pop culture. Oxford University Press. ISBN 978-0-19-939024-3. OCLC 878953765. 
• Mallinson, James; Singleton, Mark (2017). Roots of Yoga. Penguin Books. ISBN 978-0-241-25304-5. OCLC 928480104. 

External links

• International Association of Yoga Therapists