Background

• Yoga is an ancient system of relaxation, exercise, and healing with origins in Indian philosophy. Early descriptions of yoga are written in Sanskrit, the classical literary language of India. The first known work is "The Yoga Sutras," written more than 2,000 years ago, although yoga may have been practiced up to 5,000 years ago. The initial concepts have been adapted over time through translation and scholarly interpretation, but the fundamental principles describing the practice of yoga in the quest of the soul remain largely intact.
• Yoga has been described as "the union of mind, body, and spirit," which addresses physical, mental, intellectual, emotional, and spiritual dimensions towards an overall harmonious state of being. The philosophy of yoga is sometimes pictured as a tree with eight branches. These eight limbs are: pranayama (breathing exercises), asana (physical postures), yama (moral behavior), niyama (healthy habit), dharana (concentration), prathyahara (sense withdrawal), dhyana (contemplation), and samadhi (higher consciousness). There are several schools of yoga practice, such as hatha yoga, karma yoga, bhakti yoga, and raja yoga. These schools vary in the proportions of the exercises of the eight limbs. However, they are all similar in working towards the goal of self-realization and control of mental, physiological, and psychological parameters through yogic experiences. In the United States and Europe, hatha yoga is commonly practiced, including pranayama and asanas.
• Yoga is often practiced by healthy individuals with the aim to achieve relaxation, fitness, and a healthy lifestyle. Yoga has also been recommended and used for a variety of medical conditions. Yoga techniques can be learned in classes or through videotape instruction. Classes last from 30 to 90 minutes and are offered at various skill levels. There is no widely accepted credentialing for yoga instructors.

References

• Bower JE, Woolery A, Sternlieb B, et al. Yoga for cancer patients and survivors. Cancer Control 2005 Jul;12(3):165-71.
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• Cohen BE, Kanaya AM, Macer JL, et al. Feasibility and acceptability of restorative yoga for treatment of hot flushes: a pilot trial. Maturitas 2-20-2007;56(2):198-204.
  View Abstract
• Duraiswamy G, Thirthalli J, Nagendra HR, et al. Yoga therapy as an add-on treatment in the management of patients with schizophrenia--a randomized controlled trial. Acta Psychiatr Scand 2007;116(3):226-232.
  View Abstract
• Garfinkel MS, Singhal A, Katz WA, et al. Yoga-based intervention for carpal tunnel syndrome: a randomized trial. JAMA 11-11-1998;280(18):1601-1603.
  View Abstract
• Garrow D, Egede LE. Association between complementary and alternative medicine use, preventive care practices, and use of conventional medical services among adults with diabetes. Diabetes Care. 2006 Jan;29(1):15-9.
  View Abstract
• Granath J, Ingvarsson S, von Thiele U, et al. Stress management: a randomized study of cognitive behavioural therapy and yoga. Cogn Behav Ther 2006;35(1):3-10.
  View Abstract
• John PJ, Sharma N, Sharma CM, et al. Effectiveness of yoga therapy in the treatment of migraine without aura: a randomized controlled trial. Headache 2007;47(5):654-661.
  View Abstract
• Kirkwood G, Rampes H, Tuffrey V, et al. Yoga for anxiety: a systematic review of the research evidence. Br J Sports Med 2005 Dec;39(12):884-91; discussion 891.
  View Abstract
• Mitchell KS, Mazzeo SE. Rausch SM, et al. Innovative interventions for disordered eating: evaluating dissonance-based and yoga interventions. Int J Eat.Disord 2007;40(2):120-128.
  View Abstract
• Oken BS, Zajdel D, Kishiyama S, et al. Randomized, controlled, six-month trial of yoga in healthy seniors: effects on cognition and quality of life. Altern Ther Health Med 2006 Jan-Feb;12(1):40-7.
  View Abstract
• Rao MR, Raghuram N, Nagendra HR, et al. Anxiolytic effects of a yoga program in early breast cancer patients undergoing conventional treatment: a randomized controlled trial. Complement Ther Med. 2009 Jan;17(1):1-8.
  View Abstract
• Sareen S, Kumari V, Gajebasia KS, et al. Yoga: a tool for improving the quality of life in chronic pancreatitis. World J Gastroenterol 1-21-2007;13(3):391-397.
  View Abstract
• Sharma VK, Das S, Mondal S, et al. Effect of Sahaj Yoga on depressive disorders. Indian J Physiol Pharmacol 2005 Oct-Dec;49(4):462-8.
  View Abstract
• Streeter CC, Jensen JE, Perlmutter RM, et al. Yoga Asana sessions increase brain GABA levels: a pilot study. J Altern Complement Med 2007;13(4):419-426.
  View Abstract
• Tekur P, Singphow C, Nagendra HR, et al. Effect of short-term intensive yoga program on pain, functional disability and spinal flexibility in chronic low back pain: a randomized control study. J Altern Complement Med. 2008 Jul;14(6):637-44.
  View Abstract