• asthma
• breathing exercises
• complementary medicine

There is considerable lay and professional interest in non-pharmacological treatments for asthma, with reports that up to one third of people with asthma resort to complementary and alternative medicines (CAM).¹ The evidence-based review undertaken for the British guidelines on the management of asthma² found the current evidence for the presence or absence of efficacy of many CAM interventions to be inadequate, and further controlled studies are encouraged. Breathing exercises and yoga have been widely used to treat asthma in Eastern and Western societies for many years, and generally centre on manipulating the respiratory pattern to reduce respiratory frequency and hyperventilation. The Butekyo breathing technique, based on the barely tenable scientific premise that asthma is caused by hyperventilation, makes sweeping claims for effectiveness in asthma.³ In spite of anecdotal reports of benefit given wide coverage in the lay press, the limited scientific scrutiny currently afforded to this technique has indicated more modest improvements in asthma outcomes, with two small controlled studies showing some benefits in symptoms and bronchodilator use although little effect on other measures of asthma severity. A Cochrane review of breathing exercises for asthma⁴ (updated in 2000 and …