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Swimming training for asthma in children and adolescents aged 18 years and under

  1. Sean Beggs1,
  2. Yi Chao Foong2,
  3. Hong Cecilia T Le2,
  4. Danial Noor2,
  5. Richard Wood-Baker3,
  6. Julia AE Walters2,*

Editorial Group: Cochrane Airways Group

Published Online: 30 APR 2013

Assessed as up-to-date: 12 JUL 2012

DOI: 10.1002/14651858.CD009607.pub2


How to Cite

Beggs S, Foong YC, Le HCT, Noor D, Wood-Baker R, Walters JAE. Swimming training for asthma in children and adolescents aged 18 years and under. Cochrane Database of Systematic Reviews 2013, Issue 4. Art. No.: CD009607. DOI: 10.1002/14651858.CD009607.pub2.

Author Information

  1. 1

    Royal Hobart Hospital, Department of Paediatrics, Hobart, Tasmania, Australia

  2. 2

    University of Tasmania, School of Medicine, Hobart, Tasmania, Australia

  3. 3

    University of Tasmania, Tasmanian School of Medicine, Hobart, Tasmania, Australia

*Julia AE Walters, School of Medicine, University of Tasmania, Hobart, Tasmania, 7000, Australia. Julia.Walters@utas.edu.au.

Publication History

  1. Publication Status: New
  2. Published Online: 30 APR 2013

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Summary of findings    [Explanations]

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

 
Summary of findings for the main comparison. Swimming training for asthma in children and adolescents aged 18 years and under

Swimming training for asthma in children and adolescents aged 18 years and under

Patient or population: children and adolescents aged 18 years and under studies with asthma
Settings: Recruited from asthma clinics. Asthma diagnosis by recognised criteria.
Intervention: Swimming training programme- meeting minimum intensity criteria (> Weekly, > 20 minutes, > 4 weeks)

OutcomesIllustrative comparative risks* (95% CI)Relative effect
(95% CI)
No of Participants
(studies)
Quality of the evidence
(GRADE)
Comments

Assumed riskCorresponding risk

ControlSwimming training

Quality of life 1
Paediatric Asthma Quality of Life Questionnaire (PAQLQ). Scale from: 1 (worse) to 7 (better).
Follow-up: mean 9 weeks
The mean change in quality of life in the control group was -1.87The mean change in quality of life in the intervention group was
0.26 (1.05 lower to 1.58 higher)
50
(1 study1)
⊕⊕⊝⊝
low2,3

Asthma symptoms
Different scales in different studies (lower scores mean fewer symptoms)
Follow-up: 6-9 weeks
The mean change in asthma symptoms ranged across control groups from
0 to -2.14 standard deviations
The mean asthma symptoms in the intervention groups was
0.06 standard deviations less
(0.58 lower to 0.47 higher) see comment
58
(2 studies)
⊕⊕⊝⊝
low3,4,5
The difference of 0.06 standard deviations would equate to a small difference on Living with Asthma Questionnaire (LWAQ) or a composite 12-point scale of < 0.5 units. The effect size is < 0.2 representing a small effect.

Exacerbations requiring hospital admissionsee commentsee commentsee commentsee comment-Outcome not reported

Exacerbations requiring a course of oral corticosteroidssee commentsee commentsee commentsee comment-Outcome not reported

Urgent asthma physician visits1
Number of times the child visited a physician's office/clinic for an asthma flare up
Follow-up: mean 2 months
The mean urgent asthma physician visits in the control group was
0.17 visits in 2 months
The mean urgent asthma physician visits in the intervention groups was
0.08 higher
(0.25 lower to 0.42 higher)
44
(1 study1)
⊕⊕⊕⊝
moderate3

Resting lung function
Forced expiratory volume (FEV1) in 1 second (litres)
Follow-up: 6-12 weeks
The mean change in resting FEV1 ranged across control groups from
0.05-0.15 litres
The mean difference in FEV1 in the intervention groups was
0.10 L higher
(0 to 0.2 higher)
113
(4 studies)
⊕⊕⊕⊝
moderate3
The mean difference is comparable to the difference in FEV1 in children with asthma (N = 4, n = 719 7) comparing low dose fluticasone propionate (100 mcg) daily with placebo mean difference (MD) 0.1 L [0.15, 0.36] (Adams 2008)

Fitness6
Maximal oxygen consumption (VO2 max)
Follow-up: mean 12 weeks
The mean VO2 max in usual care control groups was
39 mL/kg/min
The mean fitness in the swimming intervention groups was
9.67 mL/kg/min higher
(5.84 to 13.51 higher)
32
(2 studies)
⊕⊕⊕⊕
high
The 25% difference for swimming compared to control in VO2 max is clinically meaningful. It is larger than the differences seen in physical activity studies in children without asthma, range 5% to 15% (Armstrong 2011) and that seen in children with asthma undertaking physical training 9% (Counil 2003).

*The basis for the assumed risk is provided in the table. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
CI: Confidence interval; FEV1 forced expiratory volume in one second; L: litres;

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 1 Control group: golf
2 High risk of attrition bias assessed in study
3 The confidence interval does not rule out a null effect or harm
4 Comparison groups differed; usual care or golf
5 Effect size < 0.2 represents small effect
6 Pooled studies with non-active usual care control group only
7 N= number of studies; n= number of participant

 

Background

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Description of the condition

Originating from the Greek word 'panting', asthma is a disease associated with chronic inflammation of the airways accompanied by hyper-reactive responses of the bronchi (Ward 2002). These heightened responses result in the obstruction of airflow, which manifests as symptoms such as coughing, wheezing, chest tightness and shortness of breath (Beilby 2006). Asthma is the most common chronic medical condition among children and is one of the most common causes of hospitalisation and medical visits in the same age group (World Health Organization Media Centre 2011). It is estimated that 235 million people have asthma, while approximately a quarter of the 40 million Americans with asthma are children under the age of 17 (American Lung Association 2010). Multiple epidemiological studies from around the world indicate that the prevalence of asthma among children and adolescents is rising (Wong 2008).

Physical activity can lead to increased airway resistance in many people with asthma, precipitating an episode of exercise-induced asthma. Fear of such episodes may lead to decreased participation in physical activity, as suggested by numerous studies that have reported that children with asthma have lower cardiorespiratory fitness than their peers (Clark 1988; Lang 2004; Welsh 2005).   

 

Description of the intervention

Several studies in children with asthma have demonstrated that physical exercise does improve aerobic fitness as well as reduce episodes of wheeze, hospitalisations, school absenteeism and, to a lesser degree, medication usage (Welsh 2005).  As a subtype of physical training, swimming is often suggested as the ideal form of physical activity for individuals with asthma. Swimming training is a structured regular exercise programme through supervised aquatic activities, which aims to increase cardiorespiratory fitness.

 

How the intervention might work

There are a number of postulated reasons as to why swimming training may be superior to other forms of physical training for children with asthma. These include, the air above the pool being warmer and humidified, low pollen count exposure, hydrostatic pressure on the chest wall reducing expiratory effort and work, relative hypoventilation due to controlled breathing leading to increased carbon dioxide and horizontal posture (Bar-Or 1992; Bernard 2010; Downing 2011; Inbar 1991; Wardell 2000). These are on top of the effects of any physical training, namely increased self-esteem, self-confidence and improved cardio-pulmonary fitness. Of note however, are the concerns raised over the past decade in relation to the potential pro-asthmatic effect of chlorine by-products in pools (Nickmilder 2007; Uyan 2009).

 

Why it is important to do this review

Asthma is an increasingly common chronic disease in many parts of the world and it has become important to identify safe and potentially beneficial exercises for the condition. Swimming is a form of exercise that has been commonly lauded as 'healthy' for people with asthma, often being implemented in guidelines without an explicit evidence base. Several reviews have been done and many emphasise the need for further research and analysis of the existing literature on the subject (Chandratilleke 2012; Fisk 2010; Goodman 2008; Ram 2000; Ram 2005). There has been no shortage of studies on the effect of swimming, often with different results and study designs. Thus it is crucial to provide a systematic analysis and critical appraisal of the current research finding and identify whether swimming is safe and beneficial for children and adolescents with asthma.

It is also important to establish the safety of swimming training for people with asthma, especially in light of the concerns about chlorinated pools (Bernard 2003; Bernard 2006a).

 

Objectives

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

To determine the effectiveness and safety of swimming training as an intervention for asthma in children and adolescents aged 18 years and under. 

 

Methods

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Criteria for considering studies for this review

 

Types of studies

We included all available randomised controlled trials (RCTs) and quasi-RCTs (i.e. using a quasi-random allocation method such as allocation by date of birth or day of the week) of children undergoing swimming training. We identified and included studies reported in abstract form and requested data from trialists where no full publication was found. We did not impose any restrictions on language, year of publication and type of publication of a study.

 

Types of participants

We included studies of children and adolescents aged 18 years and under, with physician-diagnosed asthma or based on objective criteria as stated in study methods, such as bronchodilator response, or both. We included studies with participants having any severity of asthma.

 

Types of interventions

We included studies with swimming training, defined as a formal swimming programme of at least one session per week, with each session lasting at least 20 minutes and running over a minimum of four weeks. Studies could have a comparison group receiving usual care without any intervention, or undertake a non-physical activity or physical activity other than swimming.

 

Types of outcome measures

We assessed the effects of interventions in these categories of outcomes where available: patient-related, health economic and objective measures of lung function, airway reactivity and inflammation

 

Primary outcomes

  1. Quality of life measured by disease specific or generic questionnaires (e.g. Paediatric Asthma Quality of Life Questionnaire (PAQLQ) (Juniper 1996).
  2. Asthma control measured by questionnaires/symptom diaries.
  3. Exacerbations of asthma requiring attendance at hospital.
  4. Systemic steroid use for exacerbations of asthma.

 

Secondary outcomes

  1. Bronchodilator use.
  2. Use of preventer medication (e.g. inhaled corticosteroids [ICS]).
  3. Lung function (including peak expiratory flow (PEF), forced expiratory volume in 1 second (FEV1),  forced vital capacity (FVC)).
  4. Exercise capacity (cardio-pulmonary fitness).
  5. Bronchial hyper-responsiveness (determined by a formal direct or indirect challenge test).
  6. Time-off required from employment or education.
  7. Utilisation of healthcare services.

 

Search methods for identification of studies

 

Electronic searches

We identified trials using the Cochrane Airways Group's Specialised Register of trials, which is derived from systematic searches of bibliographic databases including the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, latest issue), MEDLINE, EMBASE, CINAHL, AMED and PsychINFO and handsearched respiratory journals and meeting abstracts (please see Appendix 1 for further details). The TSC searched all records in the Specialised Register coded as 'asthma' using the following terms: swim* or pool* or ((water* or aquatic*) and exercise*). We conducted additional searches of CENTRAL, PubMed, CINAHL and EMBASE. See Appendix 2 for the search strategies. Searches were conducted in November 2011. A repeat search of Cochrane Central Register of Controlled Trials (CENTRAL) database in July 2012 did not find any new studies.

We conducted a search of national and international trial registers including The Australian New Zealand Clinical Trials Registry, Chinese Clinical Trial Register, ClinicalTrials.gov register, Current Controlled Trials metaRegister of Controlled Trials (mRCT) – active registers, Hong Kong clinical trials register, International Clinical Trials Registry Platform Search Portal, South African National Clinical Trial Register and UK Clinical Trials Gateway. We searched all databases from their inception to the present, with no restriction on language of publication.

 

Searching other resources

We checked reference lists of all studies assessed to identify other relevant studies. We consulted experts in the field for ongoing or unpublished studies. We contacted the author(s) of any identified abstracts or unpublished studies to ascertain the study design and outcome measures. We included abstracts and unpublished studies if sufficient information on the study design was available, but only included them in the meta-analysis where we had data on outcome measures.

 

Data collection and analysis

 

Selection of studies

At least two review authors (YF, HL, WN) independently identified studies and assessed whether they met the inclusion criteria. We resolved any discrepancies through consultation with a third review author (JW, RWB, or SB). The review authors initially identified studies for inclusion based on citation and abstract but if there was insufficient information to make a determination, we retrieved the full article. We eliminated duplicate studies by comparing authors' names and titles of studies.

 

Data extraction and management

At least two review authors (JW, WN, HL, YF) independently extracted and entered data onto a standard extraction form.

We extracted the following characteristics.

  • Methods: study design, location, number of centres, duration of study; methods of analysis.
  • Participants: recruitment, target participants, N screened, N randomised, N completed, asthma diagnosis criteria, severity of asthma, gender, age, other inclusion criteria, exclusion criteria.
  • Interventions: setting of intervention:  indoor/outdoor, chlorinated/non-chlorinated; swimming training supervisor; description of intervention:  length session/frequency, duration; control; co-interventions.
  • Outcomes: pre-specified, follow-up period.

Coding for subgroup analysis: adolescents/children; asthma mild/moderate/severe, length swimming session, indoor/outdoor pool, chlorinated/non-chlorinated.

Any discrepancies were resolved though consultation with a third review author.

 

Assessment of risk of bias in included studies

Two review authors (YF, HL, WN) independently assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). Since it was not possible to blind participants in these studies this criterion was not assessed. Disagreement was resolved by discussion or by involving a  third review author (JW). We examined 'Risk of bias' assessment through the synthesis of a 'Risk of bias' table.

We assessed the risk of bias according to the following domains.

  1. Random sequence generation.
  2. Concealment of allocation.
  3. Blinding of assessors.
  4. Incomplete outcome data.
  5. Selective outcome reporting.

We noted any other potential sources of bias. We graded each domain as having 'low', 'high' or 'unclear' risk of bias.

 

Measures of treatment effect

If studies used the same scale to measure a continuous outcome, for example lung function or asthma medication use, we calculated mean differences (MDs) and 95% confidence intervals (CIs) using change from baseline where data were available. However, if the measurements pre- and post intervention were unavailable we used the absolute values in the groups. Where different scales were used to measure a continuous outcome, we calculated a standardised mean difference (SMD) and 95% CI. We determined the minimum threshold for a clinically significant effect for outcomes such as asthma control, via established published standards.

For dichotomous outcomes (exacerbations of asthma or adverse events), we expressed results as Peto odds ratio (Peto OR) with 95% CI.

 

Dealing with missing data

We assessed categories of missing data under missing outcomes, missing summary data and missing individuals as in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We noted missing or unclear data on data collection forms and contacted trial authors for clarification. We also asked study authors to provide data for unreported outcomes. We assumed that loss of participants occurring prior to performance of baseline measurements had no effect on the eventual outcome data for that study. We addressed missing standard deviations by imputing data, either using studies in the same meta-analysis or for changes from baseline (Abrams 2005), calculating a correlation coefficient from baseline and final measurements for outcomes available in other studies (see  Table 1). We used the correlation coefficients to calculate and impute the standard deviation of change from baseline. We explored the impact of imputation in the overall assessment of results by sensitivity analyses.

 

Assessment of heterogeneity

We used the I2 statistic to measure heterogeneity among the trials in each analysis Higgins 2011. Interpretation of statistical heterogeneity was according to the recommendation of Higgins 2011, as follows:

  • 0% to 40%: might not be important;
  • 30% to 50%: may represent moderate heterogeneity;
  • 50% to 90%: may represent substantial heterogeneity;

Where substantial heterogeneity ( I2 > 50%) was identified, we explored it using pre-specified subgroup analyses where possible. 

 

Assessment of reporting biases

Where reporting bias was indicated (see 'Selective reporting bias' above), we attempted to contact study authors to ask them to provide missing outcome data.

 

Data synthesis

We combined studies that measured the same outcome in meta-analyses where data were available. Where there was a high level of heterogeneity we considered three options; not conducting a meta-analysis, exploring causes of heterogeneity and conducting a random-effects meta-analysis.

 

Subgroup analysis and investigation of heterogeneity

We pre-specified subgroup analyses between the following groups where sufficient studies could be included.

  1. Purely observed versus non-physical versus physical (non-swimming) controls.
  2. People under 12 years of age, and those 12 years and above.
  3. Severity of asthma as defined in the included studies.
  4. Length of swimming session.
  5. Chlorinated versus non-chlorinated indoor pools.
  6. Indoor versus outdoor pools.

 

Sensitivity analysis

We identified studies with a high risk bias random sequence generation, concealment of allocation, incomplete outcome data or selective outcome reporting and conducted sensitivity analyses (by excluding these studies). We did not consider blinding as this was not possible due to the nature of the intervention. Pooled results obtained using absolute outcome values were compared with pooled results using change values in sensitivity analyses presented in  Table 2 and  Table 3. Pooled results using standard deviations for change values were compared when calculated from coefficients from different studies in sensitivity analyses presented in  Table 2 and  Table 3.

 

Results

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Description of studies

See: Characteristics of included studies; Characteristics of excluded studies.

 

Results of the search

See Figure 1

 FigureFigure 1. PRISMA flow diagram

There were 1520 citations identified from the initial search of the pre-specified databases but no relevant studies from trial registers. Three additional articles were retrieved following handsearching of reference lists of potentially relevant studies and another two were added from studies included in a Cochrane Systematic Review entitled 'Physical training for asthma' (Chandratilleke 2012)'. There were a total of 1367 citations after duplicates were removed, of which 1242 were removed after title screening by two review authors. The remaining 125 articles were screened by two review authors based on their abstracts. From this, 40 were identified as potentially relevant and full text articles were retrieved. Additional data on eligibility were requested from trial authors if required, following which at least two review authors independently agreed that eight articles fulfilled the study inclusion criteria of the review (Altintas 2003; Matsumoto 1999; Varray 1991; Varray 1995; Wang 2009; Weisgerber 2003; Weisgerber 2008; Wicher 2010). The remaining 32 citations were excluded and reasons for exclusion have been specified. See Characteristics of excluded studies.

 

Included studies

See Characteristics of included studies and  Table 4 and  Table 5.

Eight studies involving 262 children or adolescents, published between 1991 and 2010, met the inclusion criteria. Sample sizes ranged from 14 to 71 participants. All studies were randomised controlled trials of children or adolescents with asthma, with swimming training in the intervention group. Swimming training programmes varied; in seven studies swimming sessions lasted for between 30 and 90 minutes, occurring two to three times a week with the length of the swimming training programme varying from six to 12 weeks. In Matsumoto 1999 the sessions were 30 minutes long but occurred six times a week for participants with severe asthma who had been recruited after an inpatient exacerbation. Seven pools were located indoors; one pool was chlorinated (Weisgerber 2008), one pool was chlorinated and well-ventilated (Wicher 2010) and one pool was non-chlorinated (Altintas 2003). In four studies chlorination status was not unspecified (Matsumoto 1999; Varray 1991; Varray 1995; Weisgerber 2003). The pool was outdoor and non-chlorinated in Wang 2009.

The comparison group was usual care without any intervention in seven studies. One study compared golf sessions for the equivalent time to the swimming group (Weisgerber 2008).

The lowest age of participants was five years (Altintas 2003). Two studies recruited children from seven or eight to 12 years (Matsumoto 1999; Wang 2009), while the upper age of participants was 13 or 14 years in five studies (Altintas 2003; Varray 1991; Varray 1995; Weisgerber 2003; Weisgerber 2008) and 18 years in one trial (Wicher 2010). The proportion of male participants varied between 44% to 88%.

Asthma diagnosis was based on guidelines specified criteria in six studies (Altintas 2003; Matsumoto 1999; Wang 2009; Weisgerber 2003; Weisgerber 2008; Wicher 2010) and in these studies asthma was specified as persistent with severity graded as severe in Matsumoto 1999, moderate in Wicher 2010 and either mild/moderate/severe in Wang 2009; Weisgerber 2003; Weisgerber 2008. Diagnosis of asthma was based on clinical criteria with atopy and bronchodilator responsiveness in two studies (Varray 1991; Varray 1995) which did not specify asthma severity.

Participants' regular medication for asthma was continued during the study in six studies but three did not specify medications used (Varray 1995; Wang 2009; Weisgerber 2003). Participants used inhaled corticosteroids in Matsumoto 1999 (52%), Weisgerber 2008 (50%). All participants in Altintas 2003 were treated with inhaled corticosteroids (100-400 mcg beclomethasone equivalent/day) and in Wicher 2010, all participants were treated with both inhaled corticosteroids (1000 mcg beclomethasone equivalent/day) and long-acting beta-agonists (formoterol 12 mcg two times a day).

 

Excluded studies

Thirty-two studies were excluded with reasons provided in Characteristics of excluded studies table. Two studies reported insufficient details about the methods of randomisation, or reported an inadequate method of allocation (Fitch 1976; Huang 1989).

 

Risk of bias in included studies

Assessment of study quality was limited by incomplete data (Figure 2).

 FigureFigure 2. Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

 

Allocation

All eight included studies were randomly allocated but of these only four had detailed descriptions regarding the method of randomisation and were judged to be at low risk of bias (Altintas 2003; Varray 1995; Weisgerber 2003; Weisgerber 2008). Only Weisgerber 2008 and Altintas 2003 supplied details regarding allocation concealment, and the other six studies were classified as unclear risk of bias for allocation.

 

Blinding

Due to the nature of the study interventions blinding of participants was not possible. All studies were classified as being of high risk for performance bias. No studies specified blinding of outcome assessors although in Matsumoto 1999 it is likely they were aware of group allocation.

 

Incomplete outcome data

Three studies with a high withdrawal rate were judged to be at high risk of bias (Weisgerber 2003; Weisgerber 2008;Wicher 2010). The remaining four studies were judged to be at low risk of bias.

 

Selective reporting

Although study protocols were not available, three studies were judged at low risk of bias. Authors of three studies responded to requests for study outcome data; Altintas 2003 supplied group results, and individual patient data were supplied for Weisgerber 2003 and Weisgerber 2008. Five studies were judged at unclear risk of bias.

 

Other potential sources of bias

No other source of bias were identified.

 

Effects of interventions

See:  Summary of findings for the main comparison Swimming training for asthma in children and adolescents aged 18 years and under

 
Primary outcomes
 
Quality of life

Only one study involving 50 participants (Weisgerber 2008) used a validated assessment tool to measure quality of life. This study reported the Pediatric Asthma Quality of Life Questionnaire (PAQLQ) (Juniper 1996); total (23 items, 1 = maximal impairment, 7 = no impairment) measuring overall functional problems for an individual with asthma (physical symptoms, emotional and social). Changes in parental quality of life were measured using the Pediatric Asthma Caregiver’s Quality of Life Questionnaire (Juniper 1996a) (PACQLQ) measuring the problems that are most troublesome to the parents (primary caregivers) of children with asthma (13 items in two domains, activity limitation and emotional function and overall score, seven-point scale, 1 = maximal impairment, 7 = no impairment).

In Weisgerber 2008, no significant differences were found between swimming and golf groups in quality of life for children PAQLQ total (mean difference (MD) 0.26; 95% confidence interval (CI) -1.05 to 1.58), or in the PAQLQ symptom domain (MD 0.07; 95% CI -1.12 to 1.26), or for caregivers' quality of life, PACQLQ total MD 0.71; 95% CI -0.83 to 2.25 ( Analysis 1.1).

 
Asthma control

Four studies (Varray 1991; Weisgerber 2003; Weisgerber 2008; Wang 2009) measured the impact of swimming on asthma symptoms. Only one study (Weisgerber 2008) used a validated assessment tool. This study reported the Living with Asthma Questionnaire Index (LWAQ index, Hyland 1991) (three items for parental report of asthma symptoms; high score indicating worse effects). In a comparison of swimming and golf exercise groups for this study (n = 50), no significant difference was found for symptoms (MD -0.10 LWAQ index: 95% CI -2.55 to 2.36) ( Analysis 1.2).

Weisgerber 2003 (n = 8) used a non validated questionnaire (score 4 better-16 worse) that assessed nocturnal coughing, daytime asthma symptoms, effect on activity and use of rescue inhaler. There was no significant difference in scores between swimming and control groups, (MD -0.80; 95% CI -4.64 to 3.04) ( Analysis 1.2).  In Wang 2009, asthma severity was assessed using the National Heart, Lung, and Blood Institute (NHLBI) criteria (symptoms: nocturnal awakening, rescue use, activity limitation). They reported a significant improvement in asthma severity post-intervention in the swimming group compared with the control group but did not show data. Varray 1991 noted symptom status in a qualitative manner with parents reporting participants in the swimming group did not have any decrease in frequency of wheezing attacks or use of regular asthma medication.

We combined the results in a meta-analysis from Weisgerber 2003 and Weisgerber 2008 (n = 58), in which symptoms were measured on differing scales, and found no statistically significant difference between swimming and control groups, (standardised mean difference (SMD) -0.06; 95% CI -0.58 to 0.47) ( Analysis 1.3; Figure 3).

 FigureFigure 3. Forest plot of comparison: 1 Swimming training versus control, outcome: 1.3 Change in asthma symptoms (all).

 
Exacerbations

No data were available for meta-analysis of number of exacerbations or exacerbation frequency. Weisgerber 2008 reported that five symptom exacerbations occurred during 700 person-sessions of the swimming programme (7.1 per 1000 sessions) and one symptom exacerbation occurred during 425 person-sessions of golf (2.4 per 1000 sessions). All episodes resolved with the use of bronchodilator and none required a clinic visit, emergency department (ED) visit, or hospitalisation. Wicher 2010 reported that no participant was admitted to hospital for asthma attacks during in the "run in" or during the training period in either the swimming or control group.

 
Corticosteroid use for exacerbations of asthma

None of the eight included studies reported data on oral steroid use during the study period.

 
Secondary outcomes

No studies reported results for bronchodilator use or time off education/work.

 
Preventer medication use

In Wicher 2010 all participants used fluticasone 500 mcg daily and authors reported that adherence to treatment with fluticasone and use of rescue salbutamol was similar in the swimming and control groups.

 
Utilisation of healthcare

Weisgerber 2008 assessed the number of times the child visited the physician's office/clinic or the ED for an asthma flare up in two months preceding the exercise intervention and during the two-month intervention period. Prior to the study, 41% had an urgent asthma physician visit (n = 44) and 18% an urgent asthma ED visit. There was a statistically significant decrease in urgent asthma physician visits in the pooled single exercise cohort analysis. Participants averaged fewer urgent visits to the clinic for asthma exacerbations during the two months they participated in the intervention compared with the prior two months, mean -1.1; SD 3.3 (P = 0.04). In separate group analyses, the decrease in urgent asthma physician visits in the swimming group (n = 27) using the Wilcoxon signed-rank test was statistically significant (P = 0.03) but not in the golf group (n = 17). However, a comparison of the swimming training and golf groups for urgent asthma physician visits over the two-month study intervention ( Analysis 1.4) did not show a significant difference (MD 0.08; 95% CI -0.25 to 0.42), and the likelihood of at least one urgent asthma physician visit was not significantly increased, (Peto odds ratio (OR) 1.64; 95% CI 0.32 to 8.44) ( Analysis 1.5). No urgent asthma ED visits occurred in the golf group during the intervention, but the likelihood was not significantly different between swimming training and golf groups (Peto OR 5.77; 95% CI 0.72 to 46.46) ( Analysis 1.5).

 
Lung function

Lung function was assessed at baseline and on completion of the intervention or control period.

FEV1: Four studies (n = 113) contributed data on FEV1 (Varray 1991; Wang 2009; Weisgerber 2003; Wicher 2010). The change in FEV1 for swimming training compared with control was small and of borderline statistical significance (MD 0.10 L; 95% CI -0.00 to 0.20), with low heterogeneity I² = 32% ( Analysis 1.6). Results for FEV1 % predicted in Wicher 2010 were not included in the meta-analyses as they did not appear compatible with FEV1 results. We requested that the trial authors check their accuracy but no response was received so data were not incorporated into the meta-analysis. In four studies (Altintas 2003; Wang 2009; Weisgerber 2003; Weisgerber 2008), FEV1 % predicted (n = 83) was significantly greater in the swimming group (MD 8.07; 95% CI 3.59 to 12.54), with moderate heterogeneity I² = 38% ( Analysis 1.7; Figure 4).

 FigureFigure 4. Forest plot of comparison: 1 Swimming training versus control, outcome: 1.7 FEV1 % predicted (change).

FVC: Four studies (n = 113) contributed data on FVC (Varray 1991; Wang 2009; Weisgerber 2003; Wicher 2010). In a random-effects meta-analysis, there was a small, statistically non-significant difference in FVC for swimming training compared with control (MD 0.10 L; 95% CI -0.07 to 0.26), with substantial heterogeneity (I² = 57%) ( Analysis 1.8). The difference in FVC % predicted in five studies (Altintas 2003; Wang 2009; Weisgerber 2003; Weisgerber 2008; Wicher 2010, n = 144) was not statistically significant (MD 3.85%; 95% CI -0.58 to 8.28), with substantial heterogeneity present (I² = 61%) ( Analysis 1.9).

FEF 25-75: Four studies reported FEF 25% to 75% as per cent predicted (Wang 2009; Weisgerber 2003; Weisgerber 2008; Wicher 2010) but only Weisgerber 2003 reported absolute values. Random-effects pooled results indicated that swimming training had a significant effect on FEF25% to 75% predicted (MD 12.63; 95% CI 2.73 to 22.53; n = 118) with substantial heterogeneity, (I² = 59%) ( Analysis 1.10). The difference between groups when measured in volume was not statistically significant, (MD 0.28 L; 95% CI-0.15 to 0.72; one study, n = 8) ( Analysis 1.11).

PEF (L/min): Peak flow was assessed in Wang 2009 and Weisgerber 2003 (n = 38) and the pooled result demonstrated substantial heterogeneity (I² = 59%). The random-effects meta-analysis favoured the swimming group compared with control (MD 62.07 L/min; 95% CI 22.84 to 101.30) ( Analysis 1.13).

 
Exercise capacity and fitness

Five studies assessed the effects of swimming on exercise capacity and fitness (Altintas 2003; Matsumoto 1999; Varray 1991; Varray 1995; Weisgerber 2008), but they used a variety of different measures. The accepted gold standard for fitness testing is maximal oxygen consumption in mL/kg/min (VO2max) during a maximal effort test in the exercise laboratory. Index Physical Work Capacity (PWC)170 is the work load performed on any type of ergometer resulting in a heart rate of 170/min and is highly correlated to VO2max. Other distance-based tests have been developed to meet the need for simpler, inexpensive ways to assess aerobic fitness in children, such as the 20-metre shuttle run, the five-minute run, the six-minute run, the 15-minute run, the one-mile run, and Cooper 12-minute walk/run test (CT12).

 
VO2max (mL/kg/min)

Varray 1991 and Varray 1995 conducted measurements in children (n = 32). Swimming training compared with usual care had a positive and significant effect on VO2 max (MD 9.67 mL/kg/min; 95% CI 5.84 to 13.51), with no heterogeneity (I2 = 0%) ( Analysis 1.14). Weisgerber 2008 compared swimming training and golf and undertook fitness testing for a subset of 19 of 45 participating children and adolescents, with no significant difference (MD -7.00 mL/kg/min; 95% CI -14.57 to 0.57) ( Analysis 1.14). Studies with usual care or golf control groups were not pooled in view of the high heterogeneity, Chi² = 14.82, df = 2 (P = 0.0006); I² = 93% (Figure 5).

 FigureFigure 5. Forest plot of comparison: 1 Swimming training versus control, outcome: 1.14 Exercise capacity: VO2 max (mL/kg/min).

 
Other measures of exercise capacity

Altintas 2003 measured Index PWC170 – the work load in watts performed on an ergometer (treadmill, cyclo ergometer) that will result with a heart rate of 170/min. The swimming group had a significantly greater PWC170 compared with the control group (MD 0.44 watts; 95% CI 0.13 to 0.75) ( Analysis 1.15).

Matsumoto 1999 (n = 16) measured aerobic capacity, defined as the work load at lactate threshold and found aerobic capacity significantly increased in all participants in the swimming training group. The difference for the swimming group compared with control for swimming ergometry was MD 0.22 kp; 95% CI 0.10 to 0.34 and for cycle ergometry (MD 6.80 kp; 95% CI 2.03 to 11.57) ( Analysis 1.15).

Results from four studies with a usual care control group (n = 74) that measured exercise capacity were pooled; Altintas 2003 (PWC170, Matsumoto 1999 (cycle ergometry), Varray 1991 and Varray 1995 (VO2max) ( Analysis 1.16; Figure 6). A difference of equivalent magnitude to the pooled VO2max result was found, with a SMD (SMD) 1.34 ; 95% CI 0.82 to 1.86, and no heterogeneity (I² = 0%).

 FigureFigure 6. Forest plot of comparison: 1 Swimming training versus control, outcome: 1.16 Exercise Capacity: Any measure (control: usual care).

 
Field fitness tests

Altintas 2003 (n = 26) found no significant difference between swimming training and usual care control groups in the six-minute walk test (MD 38.64 metres; 95% CI -9.07 to 86.35) ( Analysis 1.17). Weisgerber 2008 found no significant difference in the Coopers 12-minute walk-run test between swimming training and golf groups (MD -112.93; 95% CI -643.28 to 417.41) ( Analysis 1.17). Pooling both studies using a SMD did not show any significant difference between swimming training compared with control, SMD 0.15; 95% CI -0.34 to 0.63, with moderate heterogeneity, I² = 52% ( Analysis 1.18).

 
Adverse effects

 
Bronchial hyper-responsiveness

Two individual studies (Matsumoto 1999; Wicher 2010) reported results for formal direct challenge tests but results in publications were incomplete and they could not be included in a meta-analysis. Matsumoto 1999 reported that the difference between the mean change in provocative concentration of histamine (PC20) causing a 20% fall in FEV1 in the training and control groups was not statistically significant (P = 0.16). Wicher 2010 (n = 61) measured the provocative concentration of methacholine PC20 causing a 20% fall in FEV1. Results for the groups separately were reported as showing a significant change in the swimming group pre- post-training, PC20 0.31 mg/mL (SD 0.25) before to 0.63 mg/mL (SD 0.78), P = 0.008. At the end of the study there was no significant difference between swimming and control groups (MD 0.41 Ln PC20; 95% CI -0.70 to1.51) ( Analysis 1.19).

 
Exercise induced bronchoconstriction

Matsumoto 1999 assessed exercise induced bronchoconstriction using swimming and cycle ergometry. The mean maximal percentage fall in FEV1 induced with the swimming and cycle ergometers' work load set to 175% LT on the relative load was measured. Although a smaller decrease in FEV1 was seen in the swimming training group, the difference between swimming and control groups was not statistically significant (MD -4.00 %; 95% CI-14.83 to 6.83) for swimming ergometry and (MD -4.99%; 95% CI -21.61 to 11.63) for cycle ergometry ( Analysis 1.20).

 
Subgroup analysis

Pre-specified subgroup analyses on children versus adolescents or observed/non-physical/physical activity control groups were not conducted due to limited number of studies. Analyses of lung function measures comparing non-chlorinated pools and ventilated chlorinated pools with chlorinated indoor pools was limited due to the small number of studies and missing outcome data ( Table 3).

 
Sensitivity analysis

Change from baseline values were used in the outcomes, Pediatric Asthma Quality of Life Questionnaire (PAQLQ), Pediatric Asthma Caregiver's Quality of Life Questionnaire (PACQLQ) and Living with Asthma Questionnaire Index (LWAQ index), FEV1, FVC FEF 25% to 75%. Analyses using absolute values are shown for comparison in  Table 2 and  Table 3. Results did not differ by direction nor greatly in magnitude.

Correlation coefficients between baseline and final measurements were calculated from two studies (Weisgerber 2003 and Weisgerber 2008) and are shown for comparison in  Table 1. We used the correlation coefficients from both to calculate and impute the standard deviation of change from baseline for lung function measures for Altintas 2003, Wang 2009 and Wicher 2010. We report effect sizes using values calculated from the larger study Weisgerber 2008 and included those calculated from Weisgerber 2003 in sensitivity analyses in  Table 2 and  Table 3. Although there were small variations in the effect sizes, the direction of difference did not change for any outcome.

 

Discussion

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Summary of main results

This review set out to determine the effectiveness of swimming training as an intervention for asthma in children and adolescents. There were no studies comparing swimming training with a usual care non-active control group for the primary outcomes, quality of life, asthma exacerbations or use of corticosteroids for asthma. No significant benefit on asthma symptoms was seen in studies comparing swimming training with any control group ( Summary of findings for the main comparison). When swimming training was compared with an active control group in one study (Weisgerber 2008), there were no differences in quality of life for children and caregivers, asthma control, exacerbations of asthma and asthma-related healthcare utilisation.

There were statistically significant benefits for swimming training on resting lung function measured at the conclusion of the swimming or control period, for FEV1, FVC and FEF 25% to 75%, expressed as absolute or percentage predicted values. The difference in FEV1 of 100 mL between swimming and control groups is clinically meaningful and comparable to that found in children with asthma treated with inhaled fluticasone propionate 100 mcg (Adams 2008). There were significant benefits for swimming training on cardio-pulmonary fitness compared to a non-active control measured by maximum oxygen uptake. The 25% difference for swimming compared to control in VO2 max is clinically meaningful. It exceeds the differences seen in a review of physical activity studies in children without asthma, range 5% to 15% (Armstrong 2011) and the 9% difference seen in children with asthma undertaking physical training (Counil 2003). When pooling VO2 max with other measures of exercise capacity, the result was of similar magnitude.

 

Overall completeness and applicability of evidence

The eight included studies randomised 262 participants who commenced an intervention, while 42 participants withdrew early ( Table 4;  Table 5). The number of studies on which conclusions are based are relatively few thus limiting available data. Four studies (Altintas 2003; Matsumoto 1999; Varray 1991; Varray 1995) that focused on cardiopulmonary fitness measures reported few withdrawals. Three studies assessed asthma control and lung function (Wang 2009; Weisgerber 2003; Weisgerber 2008) while one study measured lung function and bronchial hyper-responsiveness (Wicher 2010). Outcomes assessing cardiopulmonary fitness, asthma symptoms and lung function were measured at baseline and at the end of the intervention or control period.

A recently published update of a review comparing the effects of physical training in participants of all ages with asthma (Chandratilleke 2012) found exercise is well-tolerated and there was no evidence of adverse effects on asthma symptoms. Our review sought to define the benefits, if any, specifically for swimming training. Since the 1970s, it has been suggested from observational studies that swimming training is not detrimental to asthma control (Fitch 1971; Fitch 1976), and benefits on asthma symptoms and control have been seen in pre - post-observational design studies (Huang 1989; Rothe 1990).

This review was unable to add to the evidence on potential harmful effects of chlorine on children and adolescents with asthma from swimming training in non-ventilated pools (Bernard 2010) as the chlorination or ventilation status was not known in four studies, thus restricting use of subgroup analysis.

The practicality of the programmes used in the studies varied from a realistic two sessions per week to a programme with six sessions a week that would be much harder to emulate and sustain outside a study environment.

 

Quality of the evidence

The eight studies included were randomised controlled trials, although limited published information and lack of response to direct request, meant six studies were classified as at unclear risk of selection bias. No studies could be classified as at low risk for detection bias due to non-blinding of outcome assessors. Attrition bias risk was classified as high in three studies, due to high withdrawal rates (Weisgerber 2003; Weisgerber 2008; Wicher 2010). In Weisgerber 2008 there was a high rate of withdrawal after randomisation but prior to commencing training in both groups (24% swimming, 17% golf). During the programme the withdrawal rate was 17% in the swimming group and 35% in the golf group. This study only assessed some outcomes (lung function and fitness tests) on a subgroup of participants (31% swimming, 31% golf). No studies were assessed as at high risk of reporting bias (Figure 2).

Using the GRADE criteria ( Summary of findings for the main comparison), the strength of the evidence from this review for the primary outcomes, quality of life and asthma control is low and further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. For the secondary outcomes, urgent asthma visits to a physician or lung function, the strength of the evidence is moderate and it is likely that further research will have an important impact on our confidence in the estimates of effect and may change the estimates. For the secondary outcome exercise capacity, the strength of the evidence from this review is graded high and further research is very unlikely to change our confidence in the estimate of effect.

 

Potential biases in the review process

Individual patient data for Weisgerber 2008 were analysed and verified by authors (JW, YCF). Correlation coefficients were calculated using the method of Abrams 2005 from studies where baseline and final measurements were available (Weisgerber 2003; Weisgerber 2008)  Table 1. The coefficients were used to impute a change-from-baseline standard deviation where this was not reported (Altintas 2003; Wang 2009; Wicher 2010). Sensitivity analysis was undertaken using coefficients from both studies. The significance or direction of effect sizes did not differ in sensitivity analysis. Study effects reported in this review are based on imputation using coefficients calculated from the large study Weisgerber 2008 where these were available or Weisgerber 2003 for other outcomes.

 

Agreements and disagreements with other studies or reviews

The conclusions of this review support physical training benefits found in a systematic review comparing all forms of physical training for people with asthma of any age (Chandratilleke 2012). It is also consistent with the observational evidence of Font-Ribera 2011 in a prospective longitudinal study following 5738 British children from birth until age 10 years, which found that swimming did not increase the risk of asthma and that swimming was associated with improved lung function and fewer respiratory symptoms, particularly among children with asthma.

 

Authors' conclusions

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

 

Implications for practice

This review indicates that swimming training is well-tolerated in children and adolescents with stable asthma, and increases lung function (moderate strength evidence) and cardio-pulmonary fitness (high strength evidence).  There was no evidence that swimming training caused adverse effects on asthma control in young people 18 years and under with stable asthma of any severity. However whether swimming is better than other forms of physical activity cannot be determined from this review. Swimming training is a generally accessible intervention, as swimming is an activity that children are frequently encouraged to be involved in, although the availability and acceptability of swimming training is likely to vary between countries.

 
Implications for research

There is a need for further adequately powered trials that assess swimming training in children and adolescents with asthma, using published, accepted and validated measures of asthma control and quality of life, under known conditions of chlorine exposure. Longer follow-up periods may enable assessment of the long-term benefits of swimming.

 

Acknowledgements

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

Yi Chao Foong, Hong Cecilia T Le and Danial Mohammed Noor Wan received an Australian Cochrane Airways Group Network scholarship for students enrolled in a Health Professional Degree sponsored by the Asthma Foundation Tasmania. We would also like to thank Dr A Varray and Dr J Wang and Prof M Weisgerber and Dr Derya Ufuk Altıntaş for responding to requests for information or providing raw or unpublished data relating to their studies.

 

Data and analyses

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
Download statistical data

 
Comparison 1. Swimming training versus control

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Quality of life1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    1.1 PAQLQ child
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.2 PAQLQ symptom domain
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    1.3 PACQLQ parent
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 2 Symptoms (change)2Mean Difference (IV, Fixed, 95% CI)Totals not selected

    2.1 LWAQ index (control golf)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    2.2 Composite score (control usual care)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 3 Change in asthma symptoms (all)258Std. Mean Difference (IV, Fixed, 95% CI)-0.06 [-0.58, 0.47]

    3.1 Control usual care
18Std. Mean Difference (IV, Fixed, 95% CI)-0.29 [-1.73, 1.16]

    3.2 Control golf
150Std. Mean Difference (IV, Fixed, 95% CI)-0.02 [-0.58, 0.54]

 4 Urgent asthma physician visits1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    4.1 Control golf
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 5 Asthma consultation (1 or more) during intervention1Peto Odds Ratio (Peto, Fixed, 95% CI)Totals not selected

    5.1 Urgent asthma Physician visit (⋧1) during intervention
1Peto Odds Ratio (Peto, Fixed, 95% CI)0.0 [0.0, 0.0]

    5.2 Urgent asthma ED visit (⋧1) during intervention
1Peto Odds Ratio (Peto, Fixed, 95% CI)0.0 [0.0, 0.0]

 6 FEV1 L4113Mean Difference (IV, Fixed, 95% CI)0.10 [-0.00, 0.20]

    6.1 Absolute
114Mean Difference (IV, Fixed, 95% CI)-0.08 [-0.44, 0.28]

    6.2 Change
399Mean Difference (IV, Fixed, 95% CI)0.11 [0.01, 0.22]

 7 FEV1 % predicted (change)483Mean Difference (IV, Fixed, 95% CI)8.07 [3.59, 12.54]

    7.1 Control usual care
364Mean Difference (IV, Fixed, 95% CI)6.55 [1.24, 11.85]

    7.2 Control golf
119Mean Difference (IV, Fixed, 95% CI)11.82 [3.48, 20.16]

 8 FVC L4113Mean Difference (IV, Random, 95% CI)0.10 [-0.07, 0.26]

    8.1 Absolute
114Mean Difference (IV, Random, 95% CI)-0.19 [-0.95, 0.57]

    8.2 Change
399Mean Difference (IV, Random, 95% CI)0.11 [-0.06, 0.28]

 9 FVC % predicted (change)5144Mean Difference (IV, Random, 95% CI)3.85 [-0.58, 8.28]

    9.1 Control usual care
4125Mean Difference (IV, Random, 95% CI)2.00 [-1.84, 5.84]

    9.2 Control golf
119Mean Difference (IV, Random, 95% CI)8.89 [2.65, 15.12]

 10 FEF 25% to 75 % predicted (change)4118Mean Difference (IV, Random, 95% CI)12.63 [2.73, 22.53]

    10.1 Control usual care
399Mean Difference (IV, Random, 95% CI)11.07 [-1.17, 23.30]

    10.2 Control golf
119Mean Difference (IV, Random, 95% CI)19.02 [3.26, 34.78]

 11 FEF 25% to 75% L1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    11.1 Absolute
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 12 FEF 50 % predicted1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    12.1 Absolute
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 13 PEF L/min238Mean Difference (IV, Random, 95% CI)62.07 [22.84, 101.30]

    13.1 Absolute
238Mean Difference (IV, Random, 95% CI)62.07 [22.84, 101.30]

 14 Exercise capacity: VO2 max (mL/kg/min)3Mean Difference (IV, Fixed, 95% CI)Subtotals only

    14.1 Control: usual care
232Mean Difference (IV, Fixed, 95% CI)9.67 [5.84, 13.51]

    14.2 Control: golf
119Mean Difference (IV, Fixed, 95% CI)-7.00 [-14.57, 0.57]

 15 Exercise Capacity: other measures (control: usual care)2Mean Difference (IV, Fixed, 95% CI)Totals not selected

    15.1 Physical Work Capacity (PWC170 watts)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    15.2 Swimming ergometry at lactic threshold (change kp)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    15.3 Cycle ergometry at lactic threshold (change watts)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 16 Exercise Capacity: Any measure (control: usual care)474Std. Mean Difference (IV, Fixed, 95% CI)1.34 [0.82, 1.86]

    16.1 VO₂max (mL/kg/min)
232Std. Mean Difference (IV, Fixed, 95% CI)1.65 [0.82, 2.49]

    16.2 Physical Work Capacity (PWC170 watts)
126Std. Mean Difference (IV, Fixed, 95% CI)1.05 [0.22, 1.88]

    16.3 Cycle ergometry at lactic threshold (change watts)
116Std. Mean Difference (IV, Fixed, 95% CI)1.32 [0.21, 2.44]

 17 Distance fitness tests-all (m)2Mean Difference (IV, Fixed, 95% CI)Totals not selected

    17.1 Coopers 12min walk-run distance (control usual care)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    17.2 6min walk distance (control golf)
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 18 Distance fitness tests-all (m)270Std. Mean Difference (IV, Fixed, 95% CI)0.15 [-0.34, 0.63]

    18.1 Coopers 12-minute walk-run distance (control usual care)
126Std. Mean Difference (IV, Fixed, 95% CI)0.60 [-0.19, 1.39]

    18.2 6min walk distance (control golf)
144Std. Mean Difference (IV, Fixed, 95% CI)-0.14 [-0.77, 0.48]

 19 Bronchial hyper-responsiveness: ln PC20 methacholine1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    19.1 Children and adolescents
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 20 Exercise induced bronchoconstriction (maximum fall in FEV1 (%)1Mean Difference (IV, Fixed, 95% CI)Totals not selected

    20.1 Swimming ergometry
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

    20.2 Cycling ergometry
1Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]

 

Appendices

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Appendix 1. Sources and search methods for the Cochrane Airways Group Specialised Register (CAGR)

 

Electronic searches: core databases


DatabaseFrequency of search

MEDLINE (Ovid)Weekly

EMBASE (Ovid)Weekly

CENTRAL (The Cochrane Library)Monthly

PsychINFO(Ovid)Monthly

CINAHL (EBSCO)Monthly

AMED (EBSCO)Monthly



 

 

Handsearches: core respiratory conference abstracts


ConferenceYears searched

American Academy of Allergy, Asthma and Immunology (AAAAI)2001 onwards

American Thoracic Society (ATS)2001 onwards

Asia Pacific Society of Respirology (APSR)2004 onwards

British Thoracic Society Winter Meeting (BTS)2000 onwards

Chest Meeting2003 onwards

European Respiratory Society (ERS)1992, 1994, 2000 onwards

International Primary Care Respiratory Group Congress (IPCRG)2002 onwards

Thoracic Society of Australia and New Zealand (TSANZ)1999 onwards



 

 

MEDLINE search strategy used to identify trials for the CAGR

 

Asthma search

1. exp Asthma/

2. asthma$.mp.

3. (antiasthma$ or anti-asthma$).mp.

4. Respiratory Sounds/

5. wheez$.mp.

6. Bronchial Spasm/

7. bronchospas$.mp.

8. (bronch$ adj3 spasm$).mp.

9. bronchoconstrict$.mp.

10. exp Bronchoconstriction/

11. (bronch$ adj3 constrict$).mp.

12. Bronchial Hyperreactivity/

13. Respiratory Hypersensitivity/

14. ((bronchial$ or respiratory or airway$ or lung$) adj3 (hypersensitiv$ or hyperreactiv$ or allerg$ or insufficiency)).mp.

15. ((dust or mite$) adj3 (allerg$ or hypersensitiv$)).mp.

16. or/1-15

 

Filter to identify RCTs

1. exp "clinical trial [publication type]"/

2. (randomised or randomised).ab,ti.

3. placebo.ab,ti.

4. dt.fs.

5. randomly.ab,ti.

6. trial.ab,ti.

7. groups.ab,ti.

8. or/1-7

9. Animals/

10. Humans/

11. 9 not (9 and 10)

12. 8 not 11

The MEDLINE strategy and RCT filter are adapted to identify trials in other electronic databases

 

Appendix 2. Additional search strategies

CENTRAL (The Cochrane Library)

#1 MeSH descriptor Asthma explode all trees
#2 asthma* or wheez*
#3 (#1 OR #2)
#4 MeSH descriptor Swimming explode all trees
#5 (swim*):ti,ab,kw
#6 MeSH descriptor Physical Education and Training, this term only
#7 ((water* or aquatic*) and exercise*)
#8 (#4 OR #5 OR #6 OR #7)
#9 (#3 AND #8)

MEDLINE (Pubmed)

(Controlled Clinical Trial OR RANDOMIZED CONTROLLED TRIAL) AND asthma AND ((Exercise) OR (swim*))

CINAHL (EBSCO)

((MH "Asthma") OR (MH "Asthma, Exercise-Induced")) AND ((MH "Swimming") OR (MH "Exercise") OR (MH "Anaerobic Exercises") OR (MH "Aquatic Exercises") OR (MH "Aerobic Exercises") OR (MH "Athletic Training") OR (MH "Athletic Training Programs") OR (MH "Education, Athletic Training") OR (MH "Training Effect (Physiology)") OR (MH "Aquatic Sports"))

EMBASE (Embase.com)

'asthma'/exp OR 'asthma' AND ('training'/exp OR 'training' OR 'swimming'/exp OR 'swimming') AND ([controlled clinical trial]/lim OR [randomised controlled trial]/lim) AND [humans]/lim

 

Contributions of authors

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

Yi Chao Foong, Hong Cecilia T Le and Danial Wan undertook research into the background for the review. Sean Beggs reviewed the background and objectives of the review. The protocol was drafted and revised by all authors. Yi Chao Foong, Hong Cecilia T Le and Danial Wan ran searches in CENTRAL, PubMed, CINAHL and EMBASE, prepared extraction forms, assessed citations for inclusion/exclusion and maintained a database of studies. Julia Walters, Yi Chao Foong, Hong Cecilia T Le and Danial Wan prepared data extraction forms, extracted data, identified missing data, entered and checked data. Julia Walters contacted authors for missing data, performed data analysis and wrote the first draft of results and discussion. All authors contributed to working and final review drafts.

 

Declarations of interest

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

None known.

 

Sources of support

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms
 

Internal sources

  • Menzies Research Institute Tasmania, Australia.
  • University of Tasmania, Australia.

 

External sources

  • Australian Cochrane Airways Group Network Scholarship, Australia.
  • Asthma Foundation of Tasmania, Australia.

 

Differences between protocol and review

  1. Top of page
  2. Summary of findings    [Explanations]
  3. Background
  4. Objectives
  5. Methods
  6. Results
  7. Discussion
  8. Authors' conclusions
  9. Acknowledgements
  10. Data and analyses
  11. Appendices
  12. Contributions of authors
  13. Declarations of interest
  14. Sources of support
  15. Differences between protocol and review
  16. Index terms

The protocol included bronchial hyper-responsiveness as a potential adverse effect of the intervention and during the review process we included exercise induced bronchoconstriction as another potential adverse effect of the intervention.

Although we intended the secondary outcomes to be listed in no particular order, we re-ordered them to better reflect the data reported in the trials.

* Indicates the major publication for the study

References

References to studies included in this review

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Characteristics of studies
  18. References to studies included in this review
  19. References to studies excluded from this review
  20. Additional references
Altintas 2003 {published and unpublished data}
  • Altintas D, Cevit O, Ergen N, Karakoc G, Inci D. The effect of swimming training on aerobic capacity and pulmonary functions in children with asthma. Allergy & Clinical Immunology International 2003;1:17.
Matsumoto 1999 {published data only (unpublished sought but not used)}
  • Matsumoto I, Araki H, Tsuda K, Odajima H, Nishima S, Higaki Y, et al. Effects of swimming training on aerobic capacity and exercise induced bronchoconstriction in children with bronchial asthma. Thorax 1999;54(3):196-201.
Varray 1991 {published and unpublished data}
  • Varray AL, Mercier JG, Terral CM, Prefaut CG. Individualized aerobic and high intensity training for asthmatic children in an exercise readaptation program: is training always helpful for better adaptation to exercise?. Chest 1991;99(3):579-86.
Varray 1995 {published and unpublished data}
  • Varray AL, Mercier JG, Prefaut CG. Individualized aerobic and high intensity training for asthmatic children in an exercise readaptation program: is training always helpful for better adaptation to exercise?. International Journal of Rehabilitation Research 1995;18(4):297-312.
Wang 2009 {published and unpublished data}
Weisgerber 2003 {published data only}
  • Weisgerber MC, Guill M, Weisgerber JM, Butler H. Benefits of swimming in asthma: effect of a session of swimming lessons on symptoms and PFTs with review of the literature. Journal of Asthma 2003;40(5):453-64.
Weisgerber 2008 {published and unpublished data}
  • Weisgerber M, Danduran M, Meurer J, Hartmann K, Berger S, Flores G. Evaluation of Cooper 12-Minute Walk/Run Test as a Marker of Cardiorespiratory Fitness in Young Urban Children with Persistent Asthma. Clinical Journal of Sport Medicine 2009;19(4):300-305 10.1097/JSM.0b013e3181b2077a.
  • Weisgerber M, Webber K, Meurer J, Danduran M, Berger S, Flores G. Moderate and vigorous exercise programs in children with asthma: safety, parental satisfaction, and asthma outcomes. Pediatric Pulmonology 2008;43(12):1175-82.
Wicher 2010 {published data only (unpublished sought but not used)}
  • Wicher IB, De Oliveira Ribeiro MAG, Marmo DB, Da Silva Santos CI, Toro AADC, Mendes RT, et al. Effects of swimming on spirometric parameters and bronchial hyperresponsiveness in children and adolescents with moderate persistent atopic asthma. Jornal de Pediatria 2010;86(5):384-90.

References to studies excluded from this review

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Characteristics of studies
  18. References to studies included in this review
  19. References to studies excluded from this review
  20. Additional references
Alison 2000 {published data only}
  • Alison J. Physical training improves asthmatic subjects' cardiopulmonary function. Australian Journal of Physiotherapy 2000;46(4):315.
Arandelovic 2007 {published data only}
Bernard 2006 {published data only}
Bonsignore 2008 {published data only}
  • Bonsignore MR, La Grutta S, Cibella F, Scichilone N, Cuttitta G, Interrante A, et al. Effects of exercise training and montelukast in children with mild asthma. Medicine and Science in Sports and Exercise 2008;40(3):405-12.
Busfield 1982 {published data only}
  • Busfield G. Asthma treatment in Norway: an exercise in rehabilitation. Nursing Mirror 1982;155:52-4.
Fitch 1971 {published data only}
  • Fitch KD, Morton AR. Specificity of exercise in exercise-induced asthma. British Medical Journal 1971;4(5787):577-81.
Fitch 1976 {published data only}
  • Fitch KD, Morton AR, Blanksby BA. Effects of swimming training on children with asthma. Archives of Disease in Childhood 1976;51(3):190-4.
Font-Ribera 2011 {published data only}
  • Font-Ribera L, Villanueva CM, Nieuwenhuijsen MJ, Zock JP, Kogevinas M, Henderson J. Swimming pool attendance, asthma, allergies, and lung function in the Avon longitudinal study of parents and children cohort. American Journal of Respiratory & Critical Care Medicine 2011;183(5):582-8.
Haluszka 1997 {published data only}
  • Haluszka J, Zaremba-Czereyski J, Tkatchouk EN, Ehrenburg IV, Gulyaeva NV, Willim G, et al. Interval normobaric hypoxic training - A new perspective of treatment in children suffering from bronchial asthma. Journal of Investigational Allergology Clinical Immunology 1997;7(5):531.
Huang 1989 {published data only}
Inbar 1980 {published data only}
Inbar 1991 {published data only}
Inbar 1993 {published data only}
  • Inbar O, Winstein Y, Daskalovic Y, Levi R, Nueman I. The effect of prone immersion on bronchial responsiveness in children with asthma. Medicine and Science in Sports and Exercise 1993;25(10):1098-102.
Kellie 2009 {published data only}
  • Kellie HS. Have asthma? Go for a swim. My Health Software 2009; Vol. 26, issue 10:16.
Lecheler 1988 {published data only}
  • Lecheler J, Biberger A, Seligmann C, Dorsch U, Hasse-Dorsch I. [Sports therapy in the treatment of pediatric bronchial asthma. Comparison of interval and continuous training]. Praxis und Klinik der Pneumologie 1988;42(7):475-8.
Mallinson 1981 {published data only}
  • Mallinson BM, Burgess DA, Cockroft C. Exercise training for children with asthma: out-patient programme and a residential experiment. Physiotherapy 1981;67:106-8.
Moreira 2008 {published data only}
  • Moreira A, Delgado L, Haahtela T, Fonseca J, Moreira P, Lopes C, et al. Physical training does not increase allergic inflammation in asthmatic children. European Respiratory Journal 2008;32(6):1570-5.
Nickmilder 2007 {published data only}
  • Nickmilder M, Bernard A. Ecological association between childhood asthma and availability of indoor chlorinated swimming pools in Europe. Occupational & Environmental Medicine 2007;64(1):37-46.
Nursing Standard 2010 {published data only}
  • Editor comment. Clinical digest - Lung function in children improves with swimming. Nursing Standard 2010;25(13):17.
Paul 1989 {published data only}
  • Paul BA. Exercise, sports and asthma. School Nurse 1989.
Pelham 1999 {published data only}
  • Pelham TW, Holt LE, Moss MA. Pulmonary function of children with asthma in selected indoor sport environments. Pediatric Exercise Science 1999;11(4):406-12.
Piacentini 2011 {published data only}
  • Piacentini GL, Baraldi E. Pro: swimming in chlorinated pools and risk of asthma: we can now carry on sending our children to swimming pools!. American Journal of Respiratory & Critical Care Medicine 2011;183(5):569-70.
Rothe 1990 {published data only}
  • Rothe T, Köhl C, Mansfeld HJ. [Controlled study of the effect of sports training on cardiopulmonary functions in asthmatic children and adolescents]. Pneumologie 1990;44(9):1110-4.
Schaar 1999 {published and unpublished data}
  • Schaar B, Platen P, Kaisser M, Jaeschke R. Swimming and roller-blading for teenagers with forms of bronchial asthma - comparative observation of the effectiveness of sport intervention [Schwimmen und Inline Skating für Teens mit Formen des Asthma bronchiale – Vergleichende Betrachtung der Effektivität sportlicher Interventionen]. Deutsche Zeitschrift fur Sportmedizin 1999;50:97.
Schmidt 1997 {published data only}
  • Schmidt SM, Ballke EH, Nuske F, Leistikow G, Wiersbitzky SKW. Influence of outpatient sports therapy on asthma bronchiale in children. Pneumologie 1997;51(8):835-41.
Silva 2006 {published data only}
  • Silva CS, Torres LAGMM, Rahal A, Terra Filho J, Vianna E O. Comparison of morning and afternoon exercise training for asthmatic children. Brazilian Journal of Medical and Biological Research 2006;39(1):71-8.
Sly 1972 {published data only}
Sockrider 2007 {published data only}
  • Sockrider M, Garvey C, Haggerty M, Fahy B, Lareau S. Asthma and exercise for children and adults. American Journal of Respiratory & Critical Care Medicine 2007;175(11):P5-6.
Svenonius 1983 {published data only}
Turner 2011 {published data only}
  • Turner S, Eastwood P, Cook A, Jenkins S. Improvements in symptoms and quality of life following exercise training in older adults with moderate/severe persistent asthma. Respiration 2011;81(4):302-10.
Wardell 2006 {published data only}
  • Wardell C, Huang S, Isbister C. When children with asthma go swimming, the benefits can be many and long-lasting. Contemporary Pediatrics 2006;23(10):89.
Zipes 2003 {published data only}
  • Zipes D. Asthma and indoor swimming pools. Medical Update 2003;29(5):7.

Additional references

  1. Top of page
  2. AbstractRésumé
  3. Summary of findings
  4. Background
  5. Objectives
  6. Methods
  7. Results
  8. Discussion
  9. Authors' conclusions
  10. Acknowledgements
  11. Data and analyses
  12. Appendices
  13. Contributions of authors
  14. Declarations of interest
  15. Sources of support
  16. Differences between protocol and review
  17. Characteristics of studies
  18. References to studies included in this review
  19. References to studies excluded from this review
  20. Additional references
Abrams 2005
Adams 2008
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American Lung Association 2010
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Armstrong 2011
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Bernard 2003
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Bernard 2006a
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Bernard 2010
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Chandratilleke 2012
Clark 1988
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Counil 2003
Downing 2011
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Fisk 2010
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Goodman 2008
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Higgins 2011
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Hyland 1991
Juniper 1996
Juniper 1996a
Lang 2004
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Ram 2005
Uyan 2009
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Ward 2002
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Wardell 2000
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