Exercise as it relates to Disease/Exercise induced asthma

Asthma is a common chronic respiratory disease. People who have asthma have sensitive airways leading to their lungs, often making it harder to breathe.
Three factors cause the difficulty to breathe:

• The inside of the airway becomes red and inflamed
• Extra mucus built up inside the airway which can block the airways, this extra mucus can influence the narrowing of the airways;
• Muscles around the airways tighten up closing the airway called “bronchoconstriction”.
  

Over 1 in 10 people in Australia have Asthma compared to 1 in 12 people in the US. An international estimate of Asthma sufferers is approximately 300 million.
There are two main types of Asthma Intermittent and Persistent, one being more severe than the other. Intermittent Asthma means that sufferers don’t posses symptoms the whole time and they have mild to severe asthma attacks from time to time. This can be well maintained with medication. Persistent Asthma is more severe and less common, sufferers have frequent symptoms and attacks.

Triggers

One form of the condition is Exercise Induced Asthma (EIA), which is triggered either before, during or after exercise. Exercise is not the only trigger for an asthma attack, others include:

• Allergies, such as dust, pollens, grasses, lawn cuttings, cat or dog etc.
• Cigarette smoke
• Cold air
• Hot dry air
• Certain medications and irritants, such as aspirin
• Emotion, including laughter
• Chest infections
• Stress

Asthma attacks are all treated the same regardless of how severe a persons asthma condition.

Asthma effects on Exercise

If a person suffers from EIA, also known as Exercise Induced Bronchoconstriction (EIB), then it can reduce their capability to compete in physical activities. Often EIA wrongly diagnosed as a lack of fitness, and therefore exercise at a disadvantage without the proper treatments. EIA and EIB are more often over-diagnosed than under-diagnosed, of the 266 athletes in the 2004 British Olympic team, asthma was misdiagnosed in 21% but undiagnosed in 2.6%.

Symptoms

Symptoms can occur within 5-20 mins after starting exercise or 5-10 upon completing brief exercise bouts.

• Coughing
• Tightness of the chest
• Wheezing
• Unusual fatigue while exercising
• Shortness of breath when exercising

Second Wave

The 'Second Wave' is an interesting phenomenon associated with asthma attacks and EIA. Occasionally symptoms of an asthma attack will start to get better and then after a short period of time can begin to worsen again, this can be because severe stress has been placed on the airway and it has become more sensitive to irritants and 'triggers'. A 'second wave' attack can last from anywhere between a few hours to several days and in some cases requires medical attention.

Treatment of Exercise Induced Asthma

There is debate on whether or not the cause of EIA is respiratory heat loss or water loss. Recent research generally accepts water loss as playing the major role, because air is normally breathed in through the nose and warmed and moistened, which doesnt occur when breathed in though the mouth (ie. During exercise). Because it is a chronic disease EIA treatment can take a long time. EIA is treated in two ways, via use of a medication or through the use of exercise. Generally medication is always used in the treatment of EIA, however the use/prescription of exercise is dependant on the severity of the condition. Most of the time it is easy to prescribe exercise to children with an asthmatic condition, however as people get older it becomes harder.

Treatments	Pros	Cons
Medications (eg. inhaled β-2 agonists)	Effective in opening the airways Easily accessible Easy to administer No severe adverse side effects	Extensive, continued use of medications can reduce sensitivity of receptors Many children are self-conscious about their condition, taking medication is not discrete, especially when use of a 'Spacer' is recommended Needs to be taken before exercise has started, can become a problem for unexpected physical activity
Exercise	Assists in living a normal healthy life Increases aerobic capacity (VO2max) Can be performed at varied intensities depending on severity and personal fitness levels	Because it is a respiratory disease, any exercise at a higher intensity than moderate is generally not achievable without showing symptoms of an oncoming attack Hard to prescribe to a person who has been previously inactive for a long time

In general it is thought that the most effective treatment of EIA or EIB is Medications and exercise be used in conjunction with each other, which allows majority of EIA sufferer to live a normal, healthy and active lifestyle.

Exercise Recommendations

It is always important to take into consideration the training environment, and in all cases avoid the presence of 'triggers' and allergens. Swimming was previously thought to be the most effective exercise for the management of asthma, while it is still highly recommended, there is now debate that swimming in an indoor environment may adversely affect a persons asthmatic condition rather than assist it, this is because of the gases release from the chemicals in the water. Exercise is split into two categories high risk and low risk activities, obviously those with more severe asthmatic conditions should seek participation in only the low risk exercise. Its also important to note that regardless of the level of risk associated with the activity it is recommended that an asthma 'action plan' be prepared in case of emergency, just having this plan can turn a high risk activity into a relatively low risk.

Low

High

Low intensity eg. walking, golf etc. Swimming (preferably outdoors where possible) Weightlifting, while it is a high intensity exercise, it does not put a great aerobic strain on the body (with caution) Activities in a warm environment where there is moisture eg. indoors, beach. Exercise with an 'action plan' in the case of an asthma attack Any activity where frequent rest periods occur Physical activity preceding a 10-15 minute moderate intensity warm up

Exercise while suffering from viral or chest infection Any activity where 'triggers' may be present Activities in cold environments eg. snow, winter sports, ice skating etc. Exercise without any use of medication or where medications are not accessible Long bouts of high intensity aerobic exercise Basketball, Long Distance Running, Soccer etc. Hot dry air

Exercise should be aiming to improve cardiorespiratory fitness without placing the participant in jeopardy of having an asthma attack. Recommended levels of exercise are around an intensity of 40-60% of one's Oxygen Uptake (VO₂max). This should be completed 3-5 times a week for between 20–60 minutes, the very unfit should be limited to 20 minutes but aim for obtaining 30 minutes minimum.

Further Information

Asthma Australia: Exercise Induced Asthma
Sports Medicine Australia: Asthma Management
National Heart Blood and Lung Institute:Asthma Guidelines (American NHLBI) and Treaments
Web MD:Medications for Treatment of Asthma
Youtube link: Asthma Overview
Nutritional Information - Mickleborough, TD, Head, SK & Lindley, MR 2011, 'Exercise-Induced Asthma: Nutritional Management', Current Sports Medicine Reports (American College of Sports Medicine), vol. 10, no. 4, pp. 197–202