Relaxation therapy in adult asthma. Is there new evidence for its effectiveness?

Studies of relaxation training for adult asthma patients were reviewed for the period between 1980 and 2000. Six controlled and three uncontrolled studies were identified, employing a variety of methods, such as progressive relaxation, functional relaxation, autogenic training, or yoga. Most studies had low sample sizes and suffered from one or more methodological deficiencies, such as suboptimal data analysis, high dropout rates, problematic measurement procedures, or insufficient descriptions of methodology and results. Overall effects on parameters of lung function, symptoms, medication consumption, and health care use were generally negligible. Problems with the underlying rationale of relaxation therapy in asthma are discussed from a psychophysiological viewpoint. Examples are given of potential beneficial and detrimental effects of these techniques on lung function with respect to emotional processes, the musculoskeletal system, and ventilation as targets of a relaxation intervention. It remains to be demonstrated that relaxation training can significantly contribute to the standard treatment of asthma in adult patients.