Treatments involving the manipulation of breathing are commonly used in routine practice by physiotherapists and other practitioners in a variety of clinical settings¹ yet, despite decades of use, there is no robust evidence base to confirm the effectiveness of these activities. Practical and logistic difficulties exist in the design and execution of the randomised controlled clinical trials required to provide the highest grade evidence for such treatments. While the design of studies investigating pharmacological agents is relatively straightforward, there are numerous potential pitfalls in trials investigating complex interventions such as breathing therapies which require significant interaction between patient and practitioner. There are obvious difficulties with devising suitable controls, blinding participants and researchers to any intervention received, and in ensuring standardisation. While it is frequently clinically acceptable to standardise medication dosage and timing, it is not normal to do so for breathing therapies—in which the response of the individual affects the intervention provided during any interaction between patient and practitioner.

STUDY OF BREATHING TECHNIQUES

In this issue of Thorax, Slader et al² present the results of a randomised double blind controlled trial comparing two breathing techniques for patients with stable but suboptimally controlled asthma. Fifty seven subjects were randomly allocated to one of two groups receiving instruction in breathing technique from educational videos, and 48 subjects completed the 30 week study. The first group of 28 subjects were instructed in a technique designed to be “active” by mimicking the hypoventilation and nasal breathing strategies advocated by the exponents of the Butekyo breathing method, and the second group of 29 subjects received an instructional video that was intended to be a more neutral control, consisting of upper chest exercises and “control of breathing” exercises focusing on posture and relaxation. Subjects …