Background: People with asthma may show less tolerance to exercise due to worsening asthma symptoms during exercise or other reasons such as deconditioning, as a consequence of inactivity. Some may also restrict activities as per medical advice or family influence and this might result in reduced physical fitness. Physical training programs aim to improve physical fitness, neuromuscular coordination and self confidence. Subjectively, many people with asthma report that they are symptomatically better when fit, but results from trials have varied and have been difficult to compare because of different designs and training protocols. Also, as exercise can induce asthma, the safety of exercise programmes need to be considered.
Objectives: To gain a better understanding of the effect of physical training on the respiratory and general health of people with asthma, from randomised trials.
Search methods: We searched the Cochrane Airways Group Specialised Register of trials up to April 2011.
Selection criteria: We included randomised trials of people over eight years of age with asthma who were randomised to undertake physical training. Physical training had to be undertaken for at least twenty minutes, two times a week, over a minimum period of four weeks.
Data collection and analysis: Two review authors independently assessed eligibility for inclusion and the quality of trials.
Main results: Nineteen studies (695 participants) were included in this review. Physical training was well tolerated with no adverse effects reported. None of the studies mentioned worsening of asthma symptoms following physical training. Physical training improved cardiopulmonary fitness as measured by a statistically and clinically significant increase in maximum oxygen uptake (MD 5.57 mL/kg/min; 95% confidence interval (CI) 4.36 to 6.78; six studies on 149 participants) and maximum expiratory ventilation (6.0 L/min, 95% CI 1.57 to 10.43; four studies on 111 participants) with no significant effect on resting lung function (performed in four studies). Although there were insufficient data to pool due to diverse reporting tools, there is some evidence available to suggest that physical training may have positive effects on health-related quality of life, with four of five studies producing a statistically and clinically significant benefit.
Authors' conclusions: This review demonstrated that physical training can improve cardiopulmonary fitness and was well tolerated among people with asthma in the included studies. As such, people with stable asthma should be encouraged to partake in regular exercise training, without fear of symptom exacerbation.