Physical training is well tolerated, leads to improvements in cardiopulmonary fitness and is not associated with adverse outcomes in people with asthma
- Department of Kinesiology, School of Recreation Management and Kinesiology, Acadia University, Wolfville, Nova Scotia, Canada
- Correspondence to: Shilpa Dogra
Department of Kinesiology, School of Recreation Management and Kinesiology, Acadia University, 550 Main St, Wolfville, Nova Scotia, Canada B4P2R6;
Commentary on: Chandratilleke MG, Carson KV, Picot J, et al. Physical training for asthma. Cochrane Database Syst Rev 2012;5:CD001116
Implications for practice and research
Regular physical activity (PA) should be recommended to those with well-controlled asthma as it leads to improvements in aerobic capacity, quality of life (QOL) and asthma symptoms.
Regular PA is safe for those with well-controlled asthma.
Randomised trials of efficacy and effectiveness must be conducted in order to determine the optimal dose and mode of PA for those with asthma.
Asthma affects 8–9% of the population in the UK. Exercise acts as a trigger for acute bronchoconstriction in approximately 80% of those with asthma.1 As such, people with asthma tend to avoid PA.1 In addition to many benefits of engaging in PA, regular exercise may lead to significant improvements in asthma control.2 This exercise paradox leaves many healthcare practitioners wondering whether they should recommend PA to their patients with asthma. A recent Cochrane review aiming to understand the effect of regular PA on asthma-related health was conducted to help elucidate this paradox.
A systematic review of randomised trials assessing the effect of participation in PA programmes on asthma symptoms, aerobic capacity, QOL and lung function was conducted. The studies reviewed were limited to PA programmes with a minimum dose of 20 min, two times per week for at least 4 weeks in duration, conducted with asthmatics aged 8 years and older. From a total of 1807 articles identified, 19 were used for qualitative analysis and 10 for quantitative analysis.
The quality of evidence for the main outcomes ranged between very low and low. This was due to small sample sizes and heterogeneity in the data. Nevertheless, based on the three studies (n=151) it was noted that participation in regular PA led to improvements in the number of symptom-free days while three other studies indicated that there were no such differences (n=70), that is, evidence suggests that asthma symptoms may improve, but certainly do not worsen with participation in regular PA. It was also found that regular PA led to improved aerobic capacity (nine studies) and QOL (five studies). No significant improvements were noted for forced expiratory volume in 1 s (n=204), forced vital capacity (n=122) or peak expiratory flow rate (n=153).
This study was conducted with great scientific rigour; however, due to limitations with the data available, the quality of evidence was not high. Furthermore, the minimum dose of PA assessed was well below the minimum recommendations for the general population, that is, 150 min/week of moderate intensity PA. Nonetheless, it appears from this review that participation in regular PA is safe for those with well-controlled asthma. This is in line with a recent systematic review which found that despite experiencing exercise-induced asthma symptoms, the risk of adverse events associated with exercise is low among those with optimal control, regardless of asthma severity.3 Given the low risk and the documented benefits of PA for general health, it is apparent that people with asthma should engage in regular PA, just as those without asthma are encouraged to do. Regular PA leads to significant improvements in aerobic capacity that leads to improved exercise efficiency, that is, an ability to perform higher-intensity activities at a lower ventilation. This leads to a significant improvement in asthma control, as limitations in activities and exacerbations become less frequent. In the current study it was noted that participants engaging in regular PA had significant improvements in aerobic capacity. This was concomitant to improved asthma symptoms. As such, it appears that an improvement in aerobic capacity leads to improved asthma symptoms. It is not surprising then that those who engage in regular PA were also noted to have better asthma-related QOL.
The findings of this review are important as they highlight the safety and benefit of engaging in regular PA for those with asthma. This study also highlights the need for randomised trials in order to properly assess the efficacy and effectiveness of PA on asthma-related health. Finally, it is apparent that restricting activities of those with asthma is counterproductive. Future research is required to determine the optimal mode and volume of PA required for those with asthma.