Studies have suggested that emotional stress may precede, accompany or exacerbate chronic or acute asthma. However, there is evidence that, in asthmatic individuals, the opposite of the normal decrease in airway resistance and increase in bronchodilation that follow psychological and exercise stress, respectively, may occur.

Dr A Huntley and colleagues from the University of Exeter conducted a review of the literature on relaxation techniques in asthma. In total, 15 randomised control trials were identified from searches of Medline, Cochrane Library, CISCOM and Embase. Six were discounted, however, because statistical comparisons between the treatment and control groups were inadequate.

Significant therapeutic effects were observed in two of five trials examining muscle or mental and muscular relaxation in asthma. Of one trial investigating hypnosis, another investigating autogenic training and two investigating biofeedback, no significantly positive therapeutic effects were observed.

The researchers comment that, overall, the quality of the trials examined was poor and that improvements in sample size, study duration, statistical analysis and outcome measures could yield more reliable results. They admit that a realistic placebo for relaxation may not be possible, however.

Dr Huntley and colleagues conclude that the poor-quality evidence inhibits effective assessment of the potential benefits of therapeutic relaxation techniques in asthmatic patients. However, they add that muscular relaxation may warrant further investigation and do not discount such an approach altogether.

Writing in the journal Thorax, they add, “Relaxation therapies with even small effect sizes, if demonstrated reliably, might be cost-effective as an adjunct to conventional pharmaceutical intervention.”

Reference: Huntley et al, Thorax 2002;57:127-131
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