Exercise and asthma: a review

Dr Olayemi Fehintola, Department of Medicine, Obafemi Awolowo University, Ile-Ife, Nigeria; and Professor G E Erhabor, Consultant Chest Physician and Professor of Medicine, Obafemi Awolowo University, Ile-Ife, Nigeria, and President of the Nigerian Thoracic Society. Correspondence to: Dr O F Awopeju. Email: [email protected] Introduction The benefits of exercise cannot be overestimated as physical activity has been shown to be protective for a variety of chronic illnesses such as hypertension, ischaemic heart diseases, type 2 diabetes, osteoporosis, colonic cancer, anxiety, and depression. Low levels of activity are associated with increased mortality; 12% of deaths in the USA can be attributed to low levels of physical activity.1 In spite of this, many asthma patients are still unwilling to undertake any exercise due to the fear of precipitating an attack and are, therefore, unfit. Studies have shown that asthma sufferers are able to exercise and improve their fitness and the limitation in exercise capacity tends to relate more to their lack of fitness rather than airflow obstruction.2 Many asthmatics have won gold medals in the Olympic games. The relationship between asthma and exercise has long been known; it was Aretaeus (120–200AD), over 1800 years ago, who noted that physical exertion provoked airway obstruction.3 Over 300 years ago, Sir John Floyer, who was himself asthmatic, described the adverse effect of physical exercise on his asthma, noting that different exercises had a greater or lesser adverse effect,4 and Herxheimer suggested that hyperventilation stimulated airway narrowing.5 While exercise-induced asthma (EIA) is a common and age-long phenomenon, many health practitioners do not have an adequate understanding of its characteristics, diagnosis, management, and prevention. The public health consequences of unrecognised or inadequately diagnosed EIA are significant: asthma was found to be the single greatest risk factor for unexplained death in a 30-year review of Israel military recruits.6 In addition, the prevalence of EIA is increasing among athletes.7 This article seeks to present a broad overview of EIA, use of objective tests for correct and precise diagnosis, and comprehensive management. Definition EIA is a condition in which vigorous physical activity triggers acute or transient airway narrowing in people with heightened airway reactivity, occurring mostly after the exercise8 and rarely during the exercise,9 resulting in a decrease in post-exercise pulmonary function. The term exercise-induced bronchoconstriction (EIB) is often used interchangeably with EIA but the former may be more appropriate when exercise is the only provoking factor in some individuals, especially elite athletes when there are no other symptoms or signs of asthma.10