Australian association for exercise and sports science position statement on exercise and asthma

Available online at www.sciencedirect.com Australian Association for Exercise and Sports Science position statement a School of Sport Science, Exercise & Health, University of Western Australia, Australia b International Olympic Medical Commission, Switzerland Received 30 August 2010; received in revised form 13 December 2010; accepted 4 February 2011 Abstract
Asthma, a chronic inflammatory disorder of the airways is associated with variable obstruction to the airways and is provoked by many triggers including exercise. The management of asthma is primarily pharmacological, but exercise, despite causing bronchoconstriction inalmost all asthmatics, is an important adjunct to treatment. With adequate control of the hyperresponsive airways obtained with inhaledcorticosteroids (ICS) and inhaled beta 2 agonists (IBA), used as both a pre-exercise preventive agent and a reliever if necessary, all asthmaticsshould benefit from an exercise program. Some have realised this benefit with such success as to become Olympic and world champions inmany sports. Exercise programs should be individually tailored, follow established guidelines and result in similar benefits to those obtainedby non-asthmatics. However asthmatics must try to avoid or minimise triggers whenever possible. A specific benefit of a physical trainingprogram is that it allows asthmatics to exercise with less bronchoconstriction at the same exercise stress, although it does not abolish or reduceairway hyperresponsiveness (AHR).
2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
Keywords: Exercise; Asthma; Asthma medications; Exercise-induced asthma; Physical activity Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Role of exercise in the treatment of asthma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exercise prescription . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contra-indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Gaps in the literature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Introduction
hyperresponsiveness (AHR) that leads to recurrent episodesof wheezing, breathlessness, chest tightness and coughing.
What is asthma? Asthma is defined as a chronic inflamma- These episodes are commonly associated with widespread, tory disorder of the airways involving many cells and cellular variable obstruction to airflow that is mostly reversible either elements. The chronic inflammation is associated with airway spontaneously or with treatment.airways may be nar-rowed by one or more of the following: • Contraction of the airway smooth muscle (bronchocon- E-mail address: (A.R. Morton).
striction), airway swelling (oedema).
1440-2440/$ – see front matter 2011 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.
A.R. Morton, K.D. Fitch / Journal of Science and Medicine in Sport 14 (2011) 312–316 • Increased production of mucus coupled with inflammatory eucapnic voluntary hyperpnoea (EVH) and hypertonic saline challenge ay hyperresponsiveness can also be • Thickening of the airways (remodelling) as a consequence confirmed by a bronchodilator test, positive if a 12% or of structural changes that are not fully reversible.
greater increase in FEV1 occurs after inhaling a rapidly actingIB There are over 2 million asthmatics in Australia includ- Because breathlessness is normal after all but low- ing: 1 in 7 primary school children, 1 in 8 teenagers, 1 in 9 intensity exercise, many asthmatics are unaware that they adults; and 385 Australians died of asthma in develop EIB post exercise. They assume that their dyspnoea is a world-wide problem affecting an estimated 300 million is just lack of fitness, fail to seek medical advice, and exercise prevalence of asthma is greatest in the first at a disadvantage because of a lack of appropriate medication.
decade of life, occurs amongst members of all races and the Because of asthma and EIB, many asthmatics avoid exercise first episode may occur at any age. It is more common in which results in low aerobic fitness and at times, obesity. By boys than girls (3:2 ratio) and in older women than older contrast, there is evidence that a number of elite athletes have y factors or “triggers” provoke asthma includ- been mistakenly diagnosed with asthma and treated but do not ing: allergens, cold air, exercise, infections, pollutants, and have either asthma or the 266 athletes in the 2004 some drugs. Allergens may be indoor, including house-dust British Olympic team, asthma was misdiagnosed in 21% but mites, pets notably cats and dogs, fungi and specific foods or outdoor, especially pollens. The primary indoor pollu- How is asthma managed? Poorly treated asthma can tant is cigarette smoke, both passive and active (smokers) be a very debilitating condition. However, by following a and also chloramines in indoor swimming pools. Outdoor suitably prepared management program, developed with a pollutants are predominately air pollutants such as particu- knowledgeable physician, an asthmatic can lead a full and late matter (PM) from combustion engines and dust from active life. An “Asthma Action Plan”a written set of the construction industry. Others include ozone, nitrogen instructions developed for each asthmatic assisting him/her oxides, sulphur dioxide and carbon monoxide. Drugs that can to recognise worsening asthma symptoms, promptly modify provoke bronchoconstriction include beta blockers and non treatment as the plan instructs and seek appropriate medical steroidal anti-inflammatory drugs (NSAID). The response to assistance. The asthmatic and his/her family must under- these triggers varies amongst asthmatics and even in the same stand how to provide asthma first-aid. Brochures covering the asthmatic at different times. The severity of asthma can range first-aid procedures are available from all State Asthma Foun- from occasional episodes of breathing discomfort to frequent dations. It is recommended that physicians also develop an serious life-threatening bouts of airways obstruction.
“EIB Action Plan” in addition to the general “Asthma Action The vast majority of asthmatics will experience bron- Plan” for their patients and emphasize that it is difficult to pre- choconstriction provoked by exercise which for many years vent EIB if asthma is not adequately controlled. As part of was termed exercise induced asthma (EIA). A small minor- the Asthma Action Plan, it is recommended that asthmatics ity develop bronchoconstriction only after exercise which purchase an inexpensive peak flow meter or FEV1 meter and some authorities have called exercise-induced bronchocon- monitor their lung function on a regular basis. Change in peak striction (EIB). However, EIB, which is a self-explanatory flow values or FEV1 values may signal the need to modify term, is employed by most experts for both and will be used dosage or type of medication. Asthma medications are cat- egorized by Global Initiative for Asthma (GINA)two There has been debate as to whether respiratory heat loss main groups: (i) Controllers and (ii) Relievers.
or water loss is the primary cause of EIB with the latter now Controllers are usually taken daily with the aim of reduc- generally accepted as having the major of the ing the inflammatory mechanisms associated with asthma.
hyperpnoea that accompanies exercise, the lungs are unable Inhaled glucocorticosteroids (ICS) including beclometha- to adequately humidify these increased volumes of inspired sone, budesonide, ciclesonide and fluticasone are the air, resulting in evaporative water loss with drying and cool- mainstay and are assisted by the long acting inhaled beta ing of the airways. This releases inflammatory mediators and 2 adrenoceptor agonists (IBA) formoterol and salmeterol, over time results in damage to the airways. These mediators, and at times, add-on agents, the leukotriene receptor antago- including prostaglandins and cysteinyl-leukotrienes, cause nists (LTRA) such as oral montelukast and/or the cromones, contraction of airway smooth muscle and altered vascular inhaled cromoglicate and nedocromil. Other controller medi- permeabilityresultant bronchoconstriction is assessed cations include oral anti-IGE therapy with omalizumab which by measuring the forced expiratory volume in one second is expensive and of value only in severe IGE-mediated aller- (FEV1) which is compared with baseline FEV1 prior to an gic asthma and oral theophylline, rarely used today.
exercise challenge. EIB is accepted by the American Tho- Relievers of which the principal group are the rapidly racic a fall of 10% or greater from the baseline acting IBA such as inhaled salbutamol and terbutaline are FEV1 after a standard exercise challenge of 6–8 min dura- effective in relieving bronchoconstriction and should be tion. Currently, exercise challenge tests are being superseded inhaled only when needed and in the lowest dose necessary.
by indirect bronchial provocation tests such as mannitol, Increased need and use of these agents is indicative of loss A.R. Morton, K.D. Fitch / Journal of Science and Medicine in Sport 14 (2011) 312–316 level of exercise can be carried out at a reduced percent- age of his or her VO2 max, so providing a lesser stimulus • Obtain good control of asthma with ICS • Add LABA and when necessary LTRA, chromones, anticholinergics matics have become elite athletes, and world and Olympic champions despite some having severe asthma. Between Ensure appropriate care of MDI and spacers episodes of asthma, in many asthmatics the cardiorespira- tory system is normal and does not interfere with physical performance. However, if an asthmatic exercises with sig- nificant airways constriction, exercise performance will be • Avoid unfavourable environmental conditions when possible Reduce the effects of cold air with masks during training Key: ICS, inhaled corticosteroids; LABA, long acting IBA; LTRA,leukotriene receptor antagonists; SABA, short (and rapid) acting IBA.
3. Exercise prescription
of control of asthma and a review of the treatment regime With the benefit of pre-exercise medication, the majority is essential. Other relievers include anticholinergics such of asthmatics can participate equally with non-asthmatics of as inhaled ipratropium and systemic glucocorticosteroids, similar size, skill and fitness level. As the training programme which are mostly taken orally for severe exacerbations of for an elite athlete in any given sport is the same regardless asthma that are unresponsive to inhaled therapy.
of whether he/she is asthmatic or non-asthmatic, only a gen- A third category, preventers, may be added when dis- eral aerobic fitness programme will be outlined here. The cussing EIB. These are the rapidly acting IBA which are management of asthma in the elite athlete, with the many inhaled pre-exercise and are very effective in preventing EIB additional problems caused by long-term intense endurance in the majority of persons. Long acting IBA are useful in phys- training, particularly in unfavourable environments, has been ical or sporting activities of longer than 90–120 min duration.
Other medications with a lesser role as preventers include Warm-up. All training sessions and games should be pre- cromones and LTRA. Daily use of IBA, both rapid acting ceded by a warm-up, which continues at least until mild and long acting, can induce tolerance with loss of their effec- sweating occurs. The warm-up should consist of rhythmic tiveness as preventers of EIB and relievers of asthma and EIB low-level activity such as walking progressing to jogging or and additionally, increased severity of asthma and EIB.
equivalents for other modes of activity. This should be fol- tolerance which is not prevented by concomitant use of ICS, lowed by some light flexibility exercises for major muscle is rapidly reversed by ceasing daily IBA for a few groups, with a special emphasis on those muscles involved in Long acting IBA should never be prescribed as monotherapy the specific activity or event. A period of strengthening exer- and must be inhaled in association with an ICS.
cises for the same muscles can also be included. An early most medications for asthma and EIB are inhaled, optimum warm-up session may produce a refractory period which is use of inhalers is important, but it is not commonly achieved.
considered to be a useful preventive time during which a Asthmatics must be taught how to use their metered dose person has a reduced propensity to develop inhaler (MDI) to ensure that all of the drug(s) is adminis- The aerobic segment. Exercise should begin at a low level tered into the lungs and not deposited in the oropharynx.
of intensity and gradually increase in severity as the fit- The use of a spacer with an MDI will assist. Care of the ness level improves. The aim should be to stress the system MDI including regular washing of the mouth piece and the without straining it. The activity should utilize large muscle groups in a rhythmic fashion such as in walking, jogging, asthmatics participating in elite sporting events, drug ther- running, cycling, swimming and various endurance game apy must meet the requirements of the World Anti-Doping activities. The intensity should be such that it exceeds the threshold required for cardiorespiratory improvement; thusan intensity of 40–60% of one’s Oxygen Uptake Reserve isrecommended. When prescribing exercise it is recommended 2. Role of exercise in the treatment of asthma
that the guidelines provided by the American College ofSports Medicine are observed.
The primary management of asthma and EIB is pharma- Duration and frequency. Each session should last between cological with exercise having a secondary role. The role 20 and 60 min and 3–5 times a week is adequate. Initially, of exercise is to assist asthmatics to lead as normal a phys- the very unfit may need to limit sessions to 20 min but should ical lifestyle as possible, which should allow participation aim to increase the duration to a minimum of 30 min. Greater in sports. Regular exercise should be part of the lifestyle improvement will occur with more frequent sessions.
of all humans to maintain health and fitness. A major ben- Exercise loading. If the asthmatic is unfit, the programme efit of regular exercise for asthmatics is improved aerobic should commence with continuous walking, as this has a low fitness (i.e. Increased VO2 max) which means that a given asthmagenicity and prepares the muscles for future higher A.R. Morton, K.D. Fitch / Journal of Science and Medicine in Sport 14 (2011) 312–316 intensity exercise. As the fitness level improves, especially 5. Contra-indications
of the musculoskeletal system, one can increase the inten-sity by progressing to low-level interval training consisting It is important to exercise only if controller and preventive of walking and jogging and later continuous running. One can medications have been administered pre-exercise. Reliever progress to high intensity exercise, using training intervals of medication, rapid acting IBA, should always be available to 10–30 s followed by 30–90 s rest periods. Many team sports reverse EIB should it occur. Should this be unsuccessful, asth- are ideal, as they require an intermittent pattern of energy matics should cease exercise or continue with caution. The expenditure. Regular or frequent participation in fitness pro- availability of a peak flow meter or FEV1 meter is prudent grams necessitates an adequate level of enjoyment and such and if the peak flow value or FEV1 value is less than 75% activities that are predominately aerobic and interesting are of normal, exercise is unwise. Performing vigorous physi- therefore preferred. In general, the prescription of training for cal activities while the airways are significantly constricted individual asthmatics should be based on the types of exercise can lead to a severe drop in the arterial oxygen saturation, they prefer. Because it is less asthmagenic and benefits the accumulation of carbon dioxide and hyperinflation of the respiratory system, swimming remains an excellent activity lungs with an increased residual volume. Severe dyspnoea for asthmatics although problems of breathing air contami- and worsening of the bronchoconstriction with fatigue of nated with chloramines in indoor pools remains a concern.
the respiratory muscles may ensue. Death from asthma dur- Whenever possible non-chlorinated indoor pools should be ing exercise is rare but can occur.diving is a sport used. If only chlorinated pools are available, outdoor loca- that poses significant dangers for all participants and this is especially true for asthmatics who are generally advised to Warm-down. Every training session or game should avoid it. Those with chronic or poorly controlled or labile be followed by a warm-down (or cool-down) segment.
asthma should never dive. In Australia, it is necessary for all This can be accomplished by continuing light rhythmic intending scuba divers to pass a diving medical examination activities such as walking until the heart rate returns performed by a diving medical doctor before being certi- to within about 20 beats min−1 of the pre-exercise level.
fied as fit to scuba dive. Recently some persons with mild to The warm-down segment should conclude with a repeti- moderate well controlled asthma have been permitted to dive.
tion of the flexibility exercise regime performed during Spirometry must not reveal chronic airways obstruction and a negative bronchial provocation test with hypertonic salineis mandatory for some physical exertioninvolved with scuba, the inhalation of dry, cold compressed 4. Special considerations
air and the possibility of inhaling salt or fresh water can causeairways obstruction, air trapping and hyperinflation of the Road cyclists and runners are at risk of developing airway lungs. This increases the chance of pulmonary barotrauma hyperresponsiveness due to inspiring significant quantities and pneumothorax as the diver returns to the surface. Baro- PM from vehicle emissions while ice athletes including trauma allows air to be introduced directly into the blood and skaters and ice hockey players have been demonstrated to travel to the brain and can cause a fatal air embolism.
be prone to AHR from inhaling PM from diesel poweredzambonis (ice resurfacing machines).swimminghas been long favoured as the optimal exercise for asthmat- 6. Gaps in the literature
ics because it provokes less EIB than running and cycling,research has demonstrated that interaction between chlo- Since a swimming study examining the effects of five rine gas and inorganic compounds causes the production months swimming training (mostly in outdoor pools) on 46 of chloramines, notably nitrogen trichloride which is highly asthmatic children was published more than three decades irritating to the lungs. These have been incriminated as a ago,w comparable studies have followed,only likely factor in increased asthma in very young onecan be construed as including an adequate period of training. There is a major need for others. Recent stud- swimming pools. Endurance athletes training in cold climates ies appear to demonstrate that many elite endurance athletes are at risk of sustaining injury to their airways because of in sports where training is performed in an environment breathing large volumes of cold dry air when respiratory which is challenging to the respiratory system such as road heat loss is superimposed on water loss. Over time, this cyclists, swimmers, skaters, ice hockey players, triathletes, may result in remodelling of the airways. Avoiding training cross country skiers and biathletes may develop asthma in extremely cold conditions and using surgical face masks and/or AHR as a consequence of years of training.
and similar devices have been beneficial during training Indeed, asthma is the most common medical condition sessions to warm and humidify the inspired air but can- experienced by Olympic athletes with >7% of athletes have been confirmed to have asthma at each Olympic Games 2006, advise asthmatics not to exercise outdoors and should be 2008 and 2010.research is necessary and also to determine if after cessation of endurance training in such A.R. Morton, K.D. Fitch / Journal of Science and Medicine in Sport 14 (2011) 312–316 environments, the AHR will cease, as shown in elite Finnish 9. Turcotte H, Langdeau JB, Thibault G, et al. Prevalence of respiratory symptoms in an athlete population. Respir Med 2003;97:955–63.
10. Dickinson JW, Whyte GP, McConnell AK, et al. Impact of changes in the IOC-MC asthma criteria: a British perspective. Thorax
2005;60:629–32.
7. Conclusions
11. National Asthma Council Australia. Asthma Management Handbook 2006, South Melbourne. The National Asthma Council of Australia; Although exercise can induce EIB, regular physical activ- ity is an important component in the management of asthma.
12. Haney S, Hancox RJ. Rapid onset of tolerance to beta-agonist bron- chodilation. Respir Med 2005;99(5):566–71.
It is critical to obtain adequate control of asthma with con- 13. Haney S, Hancox RJ. Recovery from bronchoconstriction and bron- chodilator tolerance. Clin Rev Allergy Immunol 2006;31(2–3):81–96.
All asthmatics should have and adhere to a personalised 14. Chowdhury BA, Dal Pan G. The FDA and safe use of long acting beta Asthma Action plan and monitoring the state of their airways 2 agonists in the treatment of asthma. NEJM 2010;362(13):1169–71.
with a peak flow meter or FEV1 meter is recommended.
The use of pre-exercise medication allows most asthmatics 16. Henriksen JM, Nielsen TT. Effect of physical training on exercise- to perform in exercise and sporting events with mild or no induced bronchoconstriction. Acta Paediatr Scand 1983;72(1):31–6.
17. McKenzie DC, McLuckie SL, Stirling DR. The protective effects The success of asthmatics at the highest levels, in almost of continuous and interval exercise in athletes with exercise-induced all sports, is testimony to the benefits of exercise in over- asthma. Med Sci Sports Exerc 1994;26(8):951–6.
18. American College of Sports Medicine. ACSM’s guidelines for exer- coming their disability and a stimulus for others to include cise testing and exercise prescription. 8th ed. Baltimore: Lippincott, physical activity and sports in their daily lives.
19. Rundell KW. Pulmonary function decay in women ice hockey play- ers: is there a relationship to ice rink air quality? Inhal Toxicol
2004;16(3):117–23.
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