Exercising with asthma: does it help?
Exercise-induced bronchoconstriction (EIB) is a common occurrence for people with asthma. During or post-exercise, the characteristic transient airway narrowing of EIB can occur as a result of airway dehydration, due to increased ventilation that comes with physical exercise. This water loss triggers an increase in airway fluid osmolarity, promoting contraction of smooth muscle in the airways, as mediators are released from airway inflammatory cells. The high probability of inducing EIB can unfortunately prevent many people with asthma from partaking in physical exercise, despite it being well-established as beneficial in improving asthma-related health outcomes.1,2 How can we encourage individuals with asthma to continue to participate in physical exercise, notwithstanding the increased likelihood of EIB occurring?
The benefits of exercising
The advantageous effects of physical exercise on asthma control have been long recognized and well-documented. Reducing the risk of exacerbations; improving exercise capacity and aerobic fitness; decreasing the likelihood and severity of EIB; reducing systemic, central and airway inflammation; lessening bronchial hyper-responsiveness; improving asthma control and quality of life—physical exercise can bring an array of benefits for people living with asthma.1,3–7 Nocturnal worsening of asthma (another common occurrence for patients) and the increased severity of symptoms that it brings has also been shown to improve with exercise. Aerobic physical exercise has been demonstrated to reduce the frequency and prevalence of nocturnal symptoms in both children and adults, yet how this occurs remains unclear.8
Which sports are recommended?
Certain exercises and sports pose a greater risk of EIB and exercise-induced asthma (EIA). Partaking in endurance sports such as cycling, and winter sports such as ice hockey can bring a higher risk of EIA or EIB for people with asthma. These exercise conditions often expose individuals to osmolar and vascular airway changes which are critical to EIA and EIB pathophysiology. Team sports such as soccer, football, basketball and baseball are considered to be medium-risk sports, as they tend to involve a continuous effort rarely lasting more than 5 to 8 minutes. Low-risk sports in terms of EIA and EIB include tennis, golf, downhill skiing, gymnastics and boxing; as physical efforts are typically of short duration and thus high ventilatory levels are not reached.2
Swimming: high-risk or low-risk?
For years swimming has been considered a safe and healthy sport for individuals with asthma, thanks to the humid air inhaled during exercise, which reduces the risk of EIA and EIB, and its beneficial impact on disease severity. Yet several studies have demonstrated that, particularly in children, the potential risk of asthma seems to rise with an increase in swimming pool attendance, a correlation that has been hypothetically associated to exposure to chlorine-based irritants such as trichloramine.2,9 However, some studies have contrastingly demonstrated the opposite, showing improved lung function and a decreased risk of asthma symptoms with increased swimming pool attendance.10 As no clear conclusion can be drawn from these disparate findings, physicians should make recommendations to individuals on a case-by-case basis, using the patient’s past experiences and unique set of symptoms to guide advice and care.
While the topic of swimming remains ambiguous, clinicians can encourage individuals with asthma to participate in recognized low-risk exercises, to help ensure negative outcomes such as EIB are avoided.
- Côté A et al. Semin Respir Crit Care Med 2018; 39(1): 19–28.
- Del Giacco SR et al. Eur Clin Respir J. 2015; 2: 10.3402/ecrj.v2.27984.
- Cotman CW et al. Trends Neurosci 2007; 30(9): 464–472.
- Pastva A et al. J Immunol 2004; 172(7): 4520–4526.
- de Freitas Dantas Gomes EL and Costa D. World J Clin Cases 2015; 3(3): 301–309.
- Carson KV et al. Cochrane Database Syst Rev 2013 (9): CD001116.
- Eichenberger PA et al. Sports Med 2013; 43(11): 1157–1170.
- Francisco CO et al. PLoS One 2018; 13(10): e0204953.
- Bernard A et al. Environ Health Perspect 2006; 114(10): 1567–1573.
- Font-Ribera L et al. Am J Respir Crit Care Med 2011; 183(5): 582–588.