Complementary Therapy: Data on yoga doesn't always stand up

There are health benefits to yoga, but research is weak, says Professor Edzard Ernst

Trial data on the benefits of yoga should be interpreted with caution

The ancient Indian practice of yoga includes stretching, breathing exercises and meditation. Indian symbols dating from 3000BC indicate it already existed then.

Most widely used in the West is Hatha yoga, which includes poses (asanas), breath control (pranayama) and meditation. The aim is to bring the body to a perfect state of health and stillness, thus achieving heightened awareness.

Yoga is believed to increase the body’s stores of vital energy (prana), and facilitate its flow within the body. Poor diet, stress and other factors are thought to block the natural flow of prana, leaving the body vulnerable.


Regular yoga induces a deep sense of relaxation and benefits include suppleness, muscular strength, a sense of well-being and reduced sympathetic drive. Yoga breathing exercises may reduce muscular spasm and expand lung capacity.

Although yoga can be easily self-taught, it is preferable to learn under supervision. Classes can vary considerably, and yoga should be practised daily and should be regarded as a long-term commitment.

Yoga has been used to help anxiety and stress, arthritis, back pain, cardiovascular, respiratory and gastrointestinal problems, headaches, insomnia, and premenstrual syndrome.

A review of six controlled trials suggests yoga could normalise cardiovascular risk factors and be a supportive therapy for CHD.

However, a Cochrane review found no conclusive evidence that it benefits epilepsy.

Individual trials have generated promising results for several conditions: depression, OCD, attention deficit hyperactivity disorder, MS, back pain, carpal tunnel syndrome, asthma, TB and diabetes.

Poor studies

Other trials suggest yoga may reduce anxiety and stress, help treat hypertension, reduce joint stiffness in osteoarthritis, and improve sleep quality for lymphoma patients, quality of life in the elderly and pregnancy outcomes.

However, the quality of many studies is poor and findings should be viewed with caution.

Extreme postures are contraindicated in pregnancy. Meditation may precipitate feelings of unreality and should therefore not be used by people with a history of psychotic or personality disorder.

Physical damage can occur from overstretching joints and ligaments. Drowsiness may occur as well and possible additive effects may exist with antihypertensive drugs.

When practised wisely, yoga is a safe method of improving general health and well-being. Its role as an adjunct to the management of a wide range of medical conditions is supported by (often weak) trial data.

Professor Ernst is professor of complementary medicine at the Peninsula Medical School, Universities of Exeter & Plymouth


Hutchinson S, Ernst E. Yoga therapy for coronary heart disease: a systematic review. Perfusion 2004; 17: 44–51.

Ramaratnam S, Sridharan K. Yoga for epilepsy. Cochrane Database Syst Rev 2000; 3.

Janakiramaiah N, et al. Antidepressant efficacy of Sudarshan Kriya Yoga (SKY) in melancholia: a randomised comparison with electroconvulsive therapy (ECT) and imipramine. J Affect Disord 2000; 57: 255–9.

Shannahoff-Khalsa D S, et al. Randomised controlled trial of yogic meditation techniques for patients with obsessive-compulsive disorder. CNS-Spectrums 1999; 4: 34–47.

Jensen P S, Kenny D T. The effects of yoga on the attention and behaviour of boys with Attention-Deficit/Hyperactivity Disorder (ADHD). J Atten Disord 2004; 7: 205–16.

Oken B S, et al. Randomised controlled trial of yoga and exercise in multiple sclerosis. Neurology 2004; 62 :2,058–64.

Galantino M L, et al. The impact of modified Hatha yoga on chronic low back pain: a pilot study. Altern Ther Health Med 2004; 10: 56–9.

Manocha R, et al. Sahaja yoga in the management of moderate to severe asthma: a randomised controlled trial. Thorax 2002; 57: 110–5.

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