Background
  |
Asthma, a chronic inflammation disorder of the airways, is the most common chronic disease in the industrialised world. Asthmatics are hypertensive to allergens (small particles in the air), chemical irritants, tobacco smoke, pollution, cold air and exercise. Exposure to an irritant results in swelling of the airway walls, spasming of the smooth muscle in the airway walls and mucous secretion, causing the airways to narrow. If left untreated (i.e. no medication) an asthma attack can occur. Symptoms of asthma attacks include wheezing, coughing, shortness of breath and chest tightness. The frequency and severity of asthma attacks can vary. In severe cases, attacks can result in hospitalisation and even fatality.
The prevalence and severity of asthma is increasing. There is growing evidence to suggest that decreased physical activity is a major contributor to this (Lucas and Platts-Mills, 2005). One hypothesis for this is that obesity, which is directly associated with a sedentary lifestyle, causes airway narrowing, increased wheezing, shortness of breath and increase release of inflammatory mediators.
Exercise and Asthma
Both the American College of Sports Medicine and the American Thoracic Society recommend exercise to be included in the management plan for asthmatics. Exercise will not cure or eliminate asthma, but can decrease symptoms by increasing pulmonary airflow (airflow in lungs) and reducing ventilatory work.
Exercise Induced Asthma (EIA)
A lot of asthmatics avoid exercise, as it is a common stimulus for asthma attacks (bronchoconstriction). It is thought that EIA occurs due to a change in ventilation patterns during exercise. As exercise intensity increases, breathing becomes faster and deeper and there is a move from nose, to mouth breathing. This causes the lining of the airways to be cooled and dried, resulting in bronchoactive mediators, such as leukotrienes and prostaglandins, being released. These trigger the airways to tighten and an attack then occurs, predominantly due to spasms in the smooth muscle of the bronchioles (small airways) in the lungs. EIA attacks do not generally occur during exercise, but after.
EIA is more common in those who’s asthma is not well managed. Individuals who have a history of EIA or abnormal shortness of breath during exercise, should consult a GP before starting an exercise program. It is possible to control EIA through a GP management plan, which includes education and medication. Once asthma is appropriately managed, it is recommended that you see an Exercise Physiologist for an appropriate, personalised program.
Risk vs Benefit of Exercise for Asthma
Research has shown that exercise is safe for asthmatics. Asthma is not a reason to avoid exercise, many athletes have successfully trained and competed with asthma, some even wining gold at the Olympics. The benefits of exercise far out way the risks, which have been discussed. The benefits include:
- decreased risk of development of other chronic diseases, including diabetes and cardiovascular disease
- improved quality of life
- improved heart and lung function
- weight control
- improved overall physical fitness
- decreased depression and anxiety.
Studies have shown other positive outcomes - such as a decrease need for medication, fewer visits to the emergency and improved spirometry (lung function) (Satta, 2000). Other research has shown that asthmatics, who are physically fit have less frequent EIA attacks.
Starting an Exercise Program
Exercise is an integral part of asthma management. When beginning an exercise program it is important that the necessary steps are taken to ensure exercise is done safely. A management plan should be closely followed, including taking all medications and controlling exposures to triggers. An Exercise Physiologist should then be consulted to perform a full fitness assessment and medical history before prescribing an exercise program suitable for your current condition. Exercise Physiologists are experts in the field of exercise prescription and have a thorough understanding of the pathophysiology of asthma and therefore will ensure that you are on a safes, effective exercise program. They will also discuss with you the necessary precautions to take to decrease the risk of an asthma attack before and after exercise.
References:
Hardman A. and Stensel D. (2003) Physical activity and health- the evidence explained, Routledege, Oxon
Lucas andPlatts-Mills (2005), Physical activity and exercise in asthma: Relevance to etiology and treatment, Journal of Allergy, 115 (5)
Satta A. (2000) Exercise training in asthma. J Sports Med Phys Fitness, 40
Skinner, James (2005), Exercise Testing and Exercise Prescription for Special Cases, Lippincott Williams and Williams, USA
Website links:
Asthma Foundation NSW: http://www.asthmansw.org.au/content.cfm?id=2178&menulink=606&subid=602&menuid=606
ACSM guidelines for asthma:
http://www.acsm.org/AM/Template.cfm?Section=brochures2&Template=/CM/ContentDisplay.cfm&ContentFileID=1309