Water-based exercise for adults with asthma

  • Review
  • Intervention

Authors


Abstract

Background

Asthma is a common condition characterised by airway inflammation and airway narrowing, which can result in intermittent symptoms of wheezing, coughing and chest tightness, possibly limiting activities of daily life. Water-based exercise is believed to offer benefits for people with asthma through pollen-free air, humidity and effects of exercise on physical function.

Objectives

To evaluate the effectiveness and safety of water-based exercise for adults with asthma.

Search methods

We searched the Cochrane Airways Group Specialised Register of Trials (CAGR), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED), PsycINFO, the Latin American and Caribbean Health Science Information Database (LILACS), the Physiotherapy Evidence Database (PEDro), the System for Information on Grey Literature in Europe (SIGLE) and Google Scholar on 13 May 2014. We handsearched ongoing clinical trial registers and meeting abstracts of the American Thoracic Society (ATS), the European Respiratory Society (ERS) and the British Thoracic Society (BTS).

Selection criteria

We included all randomised controlled trials (RCTs) of adults with asthma comparing a water-based exercise group versus one or more of the following groups: usual care, land-based exercise, non-exercise.

Data collection and analysis

Two review authors (AJG, VS) independently extracted data from the primary studies using a standard form developed for this purpose, which includes methods, participants, interventions and outcomes. We contacted trial authors to request additional data. Data were input by one review author and were double-checked by a second review author.

Main results

In this systematic review, we provide a narrative synthesis of available evidence from three small studies including 136 adult participants. The studies were at high risk of bias. No meta-analysis was possible because of methodological and interventional heterogeneity between included studies. The primary outcomes of quality of life and exacerbations leading to use of steroids were not reported by these studies. For exacerbations leading to health centre/hospital visits, uncertainty was wide because a very small number of events was reported (in a single study). Secondary outcomes symptoms, lung function, changes in medication and adverse effects, where available, described for each included study. The overall quality of the studies was very low, and no clear differences were noted between water-based exercise and comparator treatments. Therefore, we remain very uncertain about the effects of water-based exercise for adults with asthma.

Authors' conclusions

The small number of participants in the three included studies, the clinical and methodological heterogeneity observed and the high risk of bias assessed mean that we are unable to assess the place of water-based exercise in asthma. Randomised controlled trials are needed to assess the efficacy and safety of water-based exercise for adults with asthma. For future research, we suggest greater methodological rigour (participant selection, blinding of outcome assessors, reporting of all outcomes analysed and registering of the study protocol).

Résumé scientifique

Exercice dans l'eau pour les adultes asthmatiques

Contexte

L'asthme est une affection fréquente caractérisée par l'inflammation et le rétrécissement des voies respiratoires, qui peuvent entraîner des symptômes intermittents de respiration sifflante, de toux et d'oppression thoracique pouvant limiter les activités de la vie quotidienne. L'exercice dans l'eau est supposé offrir des avantages pour les personnes asthmatiques grâce à l'air sans pollen, l'humidité et les effets de l'exercice sur la fonction physique.

Objectifs

Évaluer l'efficacité et la sécurité de l'exercice dans l'eau pour les adultes asthmatiques.

Stratégie de recherche documentaire

Nous avons effectué des recherches dans le registre spécialisé du groupe Cochrane sur les voies respiratoires (CAGR), le registre Cochrane des essais contrôlés (CENTRAL), MEDLINE, EMBASE, CINAHL (Cumulative Index to Nursing and Allied Health Literature), AMED (Allied and Complementary Medicine Database), PsycINFO, LILACS (Literatura Latino Americana em Ciências da Saúde), PEDro (Physiotherapy Evidence Database), le système d'information sur la littérature grise en Europe (SIGLE) et Google Scholar, le 13 mai 2014. Nous avons procédé à une recherche manuelle des registres d'essais cliniques en cours et des résumés de conférences de l'American Thoracic Society (ATS), la European Respiratory Society (ERS) et la British Thoracic Society (BTS).

Critères de sélection

Nous avons inclus tous les essais contrôlés randomisés (ECR) portant sur des adultes asthmatiques et comparant un groupe d'exercice dans l'eau à un ou plusieurs des groupes suivants : soins habituels, exercice au sol, absence d'exercice.

Recueil et analyse des données

Deux auteurs de la revue (AJG, VS) ont indépendamment extrait les données des études primaires à l'aide d'un formulaire standard élaboré à cet effet, qui comprend les méthodes, les participants, les interventions et les résultats. Nous avons contacté des auteurs d'essais pour demander des données supplémentaires. Les données ont été saisies par un auteur de la revue et contre-vérifiées par un deuxième auteur.

Résultats principaux

Dans cette revue systématique, nous fournissons une synthèse narrative des preuves disponibles à partir de trois petites études portant sur 136 participants adultes. Les études étaient à risque élevé de biais. Aucune méta-analyse n'a été possible en raison de l'hétérogénéité des méthodes et interventions dans les études incluses. Les critères de jugement principaux de la qualité de vie et des exacerbations résultant en l'administration de corticoïdes n'étaient pas rapportés par ces études. Pour les exacerbations entraînant une consultation au centre de soins / à l'hôpital, l'incertitude était grande, car un très petit nombre d'événements avait été signalé (dans une seule étude). Les critères secondaires sur les symptomes, la fonction pulmonaire, les changements de médicament et les effets indésirables ont été décrits pour chaque étude incluse lorsqu'ils étaient disponibles. La qualité globale des études était très faible, et aucune différence claire n'a été observée entre l'exercice dans l'eau et les traitements de comparaison. Par conséquent, nous restons très incertains des effets de l'exercice dans l'eau pour les adultes asthmatiques.

Conclusions des auteurs

En raison du petit nombre de participants dans les trois études incluses, de l'hétérogénéité clinique et méthodologique observée et du risque de biais jugé élevé, nous ne sommes pas en mesure d'évaluer la place de l'exercice dans l'eau dans le traitement de l'asthme. Des essais contrôlés randomisés sont nécessaires pour évaluer l'efficacité et la sécurité de l'exercice dans l'eau pour les adultes asthmatiques. Pour les recherches futures, nous recommandons une plus grande rigueur méthodologique (sélection des participants, aveuglement des évaluateurs de résultats, consignation de tous les critères analysés et enregistrement du protocole de l'étude).

Notes de traduction

Traduction réalisée par le Centre Cochrane Français

Plain language summary

Is water-based exercise an effective and safe type of exercise for adults with asthma?

Asthma is a common condition in which inflammation and narrowing of the air conducting tubes may cause intermittent symptoms, possibly limiting activities of daily life. Some adults believe that exercise could trigger an asthma attack. However, research has shown the opposite—that adults who exercise may have less chance of having an asthma attack, and taking exercise in water may be more beneficial than taking exercise on land. In this review, we aimed to evaluate the effect and safety of water-based exercise for adults with asthma.

We found a total of three studies involving 136 participants with an average age between 33 and 36 years with well-controlled asthma. They underwent water-based exercise from 40 to 60 minutes three to five times a week; the programme lasted 10 to 24 weeks in two studies, and one day only in one study.

We considered data reported on quality of life, asthma general symptoms or asthma exacerbations, measure of lung function (FEV1, forced expiratory volume of the lung in the first second of air expired) and adverse events. The quality of evidence is very low because of issues with selection of participants, small number of participants, differences in exercise duration and intensity and differences in levels of asthma. Often surrogate endpoints were measured instead of patient-important outcomes.

To sum up, more studies are needed to find out the effect and safety of water-based exercise for adults with asthma. The quality of evidence is very low because of issues with selection of participants, differences in exercise duration and intensity and differences in levels of asthma; surrogate endpoints were measured instead of patient-important outcomes.

This plain language summary is current as of 13 May 2014.

Résumé simplifié

L'exercice dans l'eau est-il un type d'exercice efficace et sûr pour les adultes asthmatiques ?

L'asthme est une maladie courante dans laquelle l'inflammation et le rétrécissement des voies respiratoires peuvent provoquer des symptômes intermittents pouvant limiter les activités de la vie quotidienne. Certains adultes croient que l'exercice pourrait déclencher une crise d'asthme. Cependant, la recherche a démontré le contraire : les adultes qui font de l'exercice pourraient avoir moins de risques de crises d'asthme, et faire de l'exercice dans l'eau pourrait être plus bénéfique que d'en faire au sol. Dans cette revue, nous avons cherché à évaluer les effets et la sécurité d'utilisation de l'exercice dans l'eau pour les adultes asthmatiques.

Nous avons trouvé un total de trois études impliquant 136 participants avec une moyenne d'âge entre 33 ans et 36 ans à l'asthme bien contrôlé. Ils ont effectué des exercices dans l'eau pendant 40 à 60 minutes trois à cinq fois par semaine ; le programme a duré 10 à 24 semaines dans deux études, et un jour seulement dans la dernière étude.

Nous avons examiné les données communiquées sur la qualité de la vie, les symptômes généraux ou les exacerbations de l'asthme, la mesure de la fonction pulmonaire (VEMS1, le volume expiratoire forcé du poumon dans la première seconde d'expiration de l'air) et les événements indésirables. La qualité des preuves est très faible en raison de problèmes dans la sélection des participants, du petit nombre de participants, de différences dans la durée et l'intensité de l'exercice ainsi que de différences dans les niveaux de l'asthme. Souvent, des critères de substitution avaient été mesurés à la place des résultats importants pour le patient.

Pour résumer, davantage d'études sont nécessaires pour déterminer l'effet et la sécurité de l'exercice dans l'eau pour les adultes asthmatiques. La qualité des preuves est très faible en raison de problèmes dans la sélection des participants, de différences dans la durée et l'intensité de l'exercice ainsi que de différences dans les niveaux de l'asthme ; des critères de substitution ont également été mesurés à la place de résultats importants pour le patient.

Ce résumé en langue simplifiée est à jour en date du 13 mai 2014.

Notes de traduction

Traduction réalisée par le Centre Cochrane Français

எளியமொழிச் சுருக்கம்

ஆஸ்துமா உடைய வயது வந்தவர்களுக்கு, நீர்-சார்ந்த உடற்பயிற்சி பயனுள்ள மற்றும் பாதுகாப்பான உடற்பயிற்சி முறையா?

ஆஸ்துமா என்பது காற்றை கடத்தும் குழாய்களில் அழற்சி மற்றும் சுருக்கத்தால், இடைப்பட்ட அறிகுறிகளை உண்டாக்கி, தினசரி வாழ்க்கை நடவடிக்கைகளை குறைக்கக்கூடிய ஒரு பொதுவான நிலை ஆகும். சில வயது வந்தவர்கள், உடற்பயிற்சியானது ஆஸ்துமா தாக்குதலை தூண்டும் என்று நம்புகிறார்கள். எனினும், ஆராய்ச்சி எதிர்மாறான காரியத்தை காட்டுகிறது-அது என்னவெனில், உடற்பயிற்சி மேற்கொள்கிற வயது வந்தவர்களுக்கு ஆஸ்துமா தாக்குதலுக்கான வாய்ப்பு குறைவாக இருக்கக்கூடும் மற்றும் நிலத்தில் உடற்பயிற்சி மேற்கொள்வதை விட நீரில் உடற்பயிற்சி மேற்கொள்வது அதிக பயனுள்ளதாக இருக்கக்கூடும். இந்த திறனாய்வில், ஆஸ்துமா உடைய வயது வந்தவர்களுக்கு நீர்-சார்ந்த உடற்பயிற்சி அளிக்கும் விளைவு மற்றும் பாதுகாப்பை மதிப்பிடுவதை நோக்கமாகக்கொண்டோம்.

நாங்கள் மொத்தமாக, நன்கு-கட்டுப்படுத்தப்பட்ட ஆஸ்துமா கொண்ட, சராசரியாக 33 முதல் 36 வயதிற்கு இடையே உள்ள 136 பங்கேற்பாளர்கள் சம்பந்தப்பட்ட மூன்று ஆய்வுகளை கண்டுபிடித்தோம். அவர்கள், 40 முதல் 60 நிமிடங்கள் வரை, ஒரு வாரத்திற்கு மூன்று முதல் ஐந்து முறை நீர்-சார்ந்த உடற்பயிற்சியை மேற்கொண்டனர்; இந்த திட்டம் இரண்டு ஆய்வுகளில் 10 முதல் 24 வாரங்கள் நீடித்தது, மற்றும் ஒரு ஆய்வில் ஒரே ஒரு நாள் மாத்திரம் நீடித்தது.

நாங்கள், வாழ்க்கை தரம், ஆஸ்துமாவின் பொது அறிகுறிகள் அல்லது ஆஸ்துமாவின் தீவிரத்தன்மை அதிகரிப்பு, நுரையீரல் செயல்பாட்டின் அளவு (FEV1,நுரையீரலில் இருந்து மூச்சு வெளிவிடுதலின் முதல் நொடியில் வெளியேற்றப்பட்ட காற்றின் கொள்ளளவு), மற்றும் பாதகமான நிகழ்வுகள் ஆகியவை பற்றிய தரவுகளைக் கருத்தில் கொண்டோம். பங்கேற்பாளர்களை தேர்வு செய்வதில் ஏற்பட்ட பிரச்சினைகள், குறைவான எண்ணிக்கையிலான பங்கேற்பாளர்கள், உடற்பயிற்சியின் கால அளவு மற்றும் தீவிரத்திலுள்ள வித்தியாசங்கள் மற்றும் ஆஸ்துமா நிலையில் உள்ள வேறுபாடுகள் காரணமாக ஆதாரத்தின் தரம் மிகவும் குறைவாக உள்ளது. பெரும்பாலும், நோயாளிகளுக்கு முக்கியமான விளைவுகளை அளவிடுவதற்கு பதிலாக துணை விளைவுகளின் முடிவுப்புள்ளிகள் அளவிடப்பட்டது .

தொகுப்பாக, ஆஸ்துமா கொண்ட வயது வந்தவர்களுக்கு நீர்-சார்ந்த உடற்பயிற்சியின் பயன் மற்றும் பாதுகாப்பைப் பற்றி கண்டுபிடிக்க இன்னும் அதிகமான ஆய்வுகள் தேவைப்படுகிறது. பங்கேற்பாளர்களை தேர்வு செய்வதில் ஏற்பட்ட பிரச்சனைகள், குறைவான பங்கேற்பாளர்கள், உடற்பயிற்சியின் கால அளவு மற்றும் தீவிரத்திலுள்ள வித்தியாசங்கள் மற்றும் ஆஸ்துமா நிலையில் உள்ள வேறுபாடுகள் ஆகியவை நிமித்தமாக ஆதாரத்தின் தரம் மிகவும் குறைவாக உள்ளது. நோயாளிகளுக்கு முக்கியமான விளைவுகளை அளவிடுவதற்கு பதிலாக துணைவிளைவுகளின் முடிவுப்புள்ளிகள் அளவிடப்பட்டது.

இந்த எளிய மொழிச் சுருக்கம் தற்போது 13 மே 2014 வரைக்குமானது.

மொழிபெயர்ப்பு குறிப்புகள்

மொழி பெயர்ப்பாளர்கள்: ப்ளசிங்டா விஜய், சிந்தியா ஸ்வர்ணலதா ஸ்ரீகேசவன், தங்கமணி ராமலிங்கம், ஸ்ரீகேசவன் சபாபதி.

Laički sažetak

Je li tjelovježba u vodi učinkovit i siguran oblik tjelovježbe za odrasle s astmom?

Astma je učestalo stanje kod kojeg upala i sužavanje dišnih putova mogu uzrokovati simptome koji se pojavljuju povremeno i tako možda ograničavaju svakodnevne aktivnosti. Neki odrasli smatraju da bi tjelovježba mogla uzrokovati astmatski napadaj. No, istraživanja su pokazala suprotno - da su odrasli koji se bave tjelovježbom pod manjim rizikom od napadaja astme te da je tjelovježba u vodi možda i korisnija od tjelovježbe na zemlji. U ovom Cochane sustavnom pregledu, htjeli smo razmotriti učinke i sigurnost tjelovježbe u vodi za odrasle s astmom.

Pronašli smo ukupno tri studije s 136 sudionika, prosječne dobi između 33 i 36 godina s dobro kontroliranom astmom. Bavili su se tjelovježbom u vodi od 40 do 60 minuta, tri do pet puta tjedno; program je trajao od 10 do 24 tjedna u dvije provedene studije i samo jedan dan u trećoj studiji.

Razmatrali smo podatke vezane uz kvalitetu života, osnovne simptome astme ili pogoršanja, razinu funkcioniranja pluća (FEV1, forsirani izdisajni volumen pluća u prvoj sekundi) i štetne učinke. Kvaliteta dokaza je jako niska zbog problematičnog izbora ispitanika, malog broja ispitanika, razlika u trajanju i intenzitetu tjelovježbe te razlika u stupnju težine bolesti. Često su promatrani zamjenski parametri umjesto rezultata koji su bitni za pacijente.

Zaključno, potreno je više studija da bi se utvrdila učinkovitost i sigurnost tjelovježbe u vodi za odrasle s astmom. Kvaliteta dokaza jako je niska zbog poteškoća s izborom ispitanika, malog broja ispitanika, razlika u trajanju i intenzitetu tjelovježbe te razlika u stupnju težine bolesti; promatrani su zamjenski parametri umjesto rezultata koji su bitni za pacijente.

Ovaj sustavni pregled uključuje studije objavljene do 13. svibnja 2104. godine.

Bilješke prijevoda

Hrvatski Cochrane
Preveo: Hrvoje Malenica
Ovaj sažetak preveden je u okviru volonterskog projekta prevođenja Cochrane sažetaka. Uključite se u projekt i pomozite nam u prevođenju brojnih preostalih Cochrane sažetaka koji su još uvijek dostupni samo na engleskom jeziku. Kontakt: cochrane_croatia@mefst.hr

Summary of findings(Explanation)

Summary of findings for the main comparison. Comparison of water-based exercise versus control for adults with asthma
  1. a(-2 risk of bias) Inadequate provision of random sequence generation and allocation concealment. Selective reporting likely.
    b(-2 inconsistency) Clinical heterogeneity due to different frequency/intensity and length of the intervention, different levels of participant asthma on baseline.
    c(-1 indirectness) Surrogate endpoints measured instead of patient-important outcomes.
    d(-1 imprecision) Small sample size compromising optimal information size (OIS)

Comparison of water-based exercise versus control for adults with asthma
Patient or population: adults with asthma
Settings: community
Intervention: water-based exercise
Comparison: control or land-based exercise
OutcomesAnalysis in study reportNo. of participants
(studies)
Quality of the evidence
(GRADE)
Comments
Quality of lifeSee commentSee commentSee commentNone of the included studies analysed this outcome using validated scales
Exacerbations leading to health centre visits or exacerbations leading to hospitalisations
Instrument: patient recorded
Follow-up: 10 weeks
No significant difference in the likelihood of an exacerbation leading to a health centre/hospital visit (RR 1.65, 95% CI 0.17 to 16.33, P value 0.67)31
(1 study)
⊕⊝⊝⊝
very low a,b,d
Parallel-group study
Lung function (FEV1 (L))
Spirometer: scale from 0.5 to 8
Follow-up: 1 to 180 days
One 24-week study showed no difference in FEV1 between water-based exercise + education versus medication (MD 0.32 L, 95% CI -0.13 to 0.77, P value 0.16). One study employing a single session of water-based breathing exercise versus land-based exercise showed no difference in FEV1 (MD -0.14 L, 95% CI -0.53 to 0.25, P value 0.48). The third study was not included for this outcome because of considerable baseline imbalance between groups105
(2 studies)
⊕⊝⊝⊝
very low a,b,c,d
Parallel-group and cross-over, respectively

Medication usage

Instrument: questionnaire
Follow-up: 10 weeks

Same medication used throughout study31
(1 study)
⊕⊝⊝⊝
very low a,b,d
Parallel-group
Adverse events
Count of events
Follow-up: 10 weeks
1 case of skin sensitivity in the water-based exercise group31
(1 study)
⊕⊝⊝⊝
very low a,b,d
Parallel-group
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.

Background

Description of the condition

Asthma is a disease characterised by inflammation of the airways, which causes airflow obstruction (CDC 2011; Lucas 2005; WHO 2011). Although frequency and intensity vary from person to person, the symptoms of asthma may include breathlessness, wheezing, coughing, chest tightness and pain (Banzett 1985; CDC 2011; WHO 2011). Epidemiological data from a survey applied in 70 countries estimate that 623 million individuals, or 8.6% (95% confidence interval (CI) 8.5 to 8.7) worldwide, are currently living with some level of asthma-related symptoms (To 2012); asthma is ranked as one of the most prevalent conditions globally. It is also important to consider the economic impact of this disease; the USA spends around US $30 billion per year on emergency department visits, physician visits and medication (CDC 2011). The Centers for Disease Control and Prevention (CDC) estimated in 2006 that 1.6 million emergency department visits and 440,000 hospitalisations in the USA were related to asthma (CDC 2011).

Description of the intervention

It may be inferred that some people with asthma are limited in the physical activities they can undertake, and that this may result in a sedentary lifestyle. Indeed, people with asthma are more likely to suffer from cardiovascular and metabolic conditions (Corbin 2011; Goodman 2008; Hildenbrand 2010). Undertaking physical activity is important for improving quality of life in people with asthma (Lucas 2005; Pedersen 2006). Water-based exercise is a good treatment option; these exercises increase muscular strength, cardiorespiratory fitness and flexibility, and they improve body composition (reducing body fat and increasing muscle mass) (Ambrosini 2010; Avelar 1999; Corbin 2011; Malkia 1998). Furthermore, muscle strength and cardiorespiratory fitness have a positive association with a reduction in the incidence of acute exacerbations (Gonçalves 2008). The most common water-based exercises described in the literature are swimming, hydrogymnastics and hydrotherapy (Denning 2012; Hildenbrand 2010).

How the intervention might work

The aquatic environment has particular properties, such as temperature of the water and humid, pollen-free air. These features have shown extra benefits in people with asthma, facilitating air exchange (Barbosa 2011; Hildenbrand 2010). Water-based exercises have therefore been widely used, as they improve breathing and increase lung volume (Aranđelović 2007). Water-based exercises also stimulate physiological pathways, which may raise forced expiratory volume in one second (FEV1) and forced vital capacity (FVC), both of which are objective measures for bronchospasm (Aranđelović 2007). Exercises increase cardiovascular fitness and, consequently, maximal consumption of oxygen (VO2max), reducing the minute ventilation required for exercise and decreasing the stimulus for bronchoconstriction. Regular and long-term exercises may be helpful in asthmatic patients and may have a positive impact on quality of life (Carson 2013). In addition, during water-based exercise, the air that is inhaled is humidified, attenuating asthma risks (O'Byrne 2012; Randolph 2009).

Why it is important to do this review

Cochrane systematic reviews for people with asthma have examined physical training (Carson 2013), breathing exercises (Freitas 2013), inspiratory muscle training (Silva 2013) and swimming training in children (Beggs 2013). However, the effectiveness and safety of water-based exercise in adults with asthma remain unclear. No systematic reviews have focused on the relationship between water-based exercise and asthma in adults. Therefore, in this systematic review, we sought to map the scientific literature and describe available evidence on this topic.

Objectives

To assess the effectiveness and safety of water-based exercise for adults with asthma.

Methods

Criteria for considering studies for this review

Types of studies

We included randomised controlled trials (RCTs), irrespective of language, age of publication or publication status. We included cross-over RCTs; however we analysed separately the data obtained from them. We planned to include cluster randomised trials.

Types of participants

We considered participants who met the following criteria.

  • Adults of either gender.

  • Adults with asthma diagnosed according to clinical criteria (American Thoracic Society (ATS), European Respiratory Society (ERS) or British Thoracic Society (BTS)) and other validated diagnostic criteria.

Types of interventions

We included studies that compared any type of water-based exercise versus another type of water-based exercise, land-based exercise or usual care. We documented the duration and frequency of sessions and the overall length of the programme. At least one group in each comparison used water-based exercise.

The following possible comparisons were made.

  • Water-based exercise versus land-based exercise.

  • Water-based exercise versus usual care.

Types of outcome measures

Primary outcomes
  • Quality of life (measured using a validated questionnaire, e.g. Asthma Quality of Life Questionnaire (AQLQ)).

  • Exacerbations (leading to a course of oral steroids; health centre visits or exacerbations; or hospitalisations).

Secondary outcomes
  • Symptoms (measured on a validated scale (e.g. Lara Asthma Symptom Scale (LASS)).

  • Lung function by physiological measures (e.g. spirometry, FEV1, FVC).

  • Reduction in medication usage (e.g. inhaled corticosteroids or leukotriene inhibitors, short-acting beta2-agonists (SABAs) or symptom controllers (e.g. long-acting beta2-agonists (LABAs)).

  • Adverse events (reactions due to the water treatment process (e.g. chlorine), exercise induced-bronchoconstriction (EIB)).

Search methods for identification of studies

Electronic searches

We identified trials from the Cochrane Airways Group Specialised Register of Trials (CAGR), which is derived from systematic searches of the main health and medical bibliographic databases (see Appendix 1 for further details). The Cochrane Airways Group Trials Search Co-ordinator searched the CAGR in May 2014 using the strategy provided in Appendix 2. We conducted additional searches on the Latin American and Caribbean Health Sciences Database (LILACS), the Physiotherapy Evidence Database (PEDro), the System for Information on Grey Literature (SIGLE) and Google Scholar. These searches were conducted in May 2014; the search strategies are reported in Appendix 3. We handsearched respiratory journals and meeting abstracts of the American Thoracic Society (ATS) from May 1994 to May 2014, the European Respiratory Society (ERS) from January 1993 to May 2014 and the British Thoracic Society (BTS) from December 2002 to May 2014.

We checked for ongoing studies in ClinicalTrials.gov (http://clinicaltrials.gov/); the metaRegister of Controlled Trials (mRCT) (http://www.controlled-trials.com/); the International Clinical Trials Registry Platform (ICTRP) (http://www.who.int/ictrp/en/); Pan African Clinical Trials (http://www.pactr.org); and the EU Clinical Trials Register (https://www.clinicaltrialsregister.eu/). These registers were searched in May 2014.

We applied no language or date restrictions. We searched all databases from their inception to the individual reported dates.

We used Endnote X6 to manage the references and excluded duplicate articles found in the different searches.

Searching other resources

We checked reference lists of all primary studies and review articles for additional references. We contacted the authors of identified trials and asked them to identify other published and unpublished studies. We also contacted exercise equipment manufacturers and experts in the field.

Data collection and analysis

We performed data collection and analysis according to recommendations provided in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011a).

Selection of studies

Two review authors (AJG, VS) independently screened titles and abstracts of all potential studies that we identified as a result of the search and coded them as 'retrieve' (eligible or potentially eligible/unclear) or 'do not retrieve.' We retrieved the full-text study reports/publications, and two review authors (AJG, VS) independently screened the full text to identify studies for inclusion. We recorded the reasons for exclusion of ineligible studies. We resolved disagreements through discussion; if required, we consulted a third person (BNGA). We identified and excluded duplicates and collated multiple reports of the same study, so that each study, rather than each report, is the unit of interest in the review. We recorded the selection process in sufficient detail to complete a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram and Characteristics of excluded studies table.

Data extraction and management

Two review authors (AJG, VS) independently extracted data from the primary studies using a standard form (Google Spreadsheet, e.g. http://goo.gl/pd0KZ) developed for this purpose, which includes methods, participants, interventions and outcomes. One review author transferred data into Review Manager (RevMan 2012). We double-checked the data by comparing data presented in the systematic review versus the study reports. A second review author spot-checked study characteristics for accuracy against the trial report.

Assessment of risk of bias in included studies

Two review authors (AJG, VS) independently assessed the risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011b). Disagreements were resolved by discussion or by involving a third review author (MSP). We assessed the risk of bias according to the following domains.

  • Random sequence generation (selection bias).

  • Allocation concealment (selection bias).

  • Blinding of participants and personnel (performance bias).

  • Blinding of outcome assessment (detection bias).

  • Incomplete outcome data (attrition bias).

  • Selective reporting (reporting bias).

  • Other bias (other sources of bias related to a particular trial design (cross-over or cluster-randomised) or to specific circumstances (interventions mixed)).

We classified the risk of bias as low, high or unclear (Higgins 2011b).

Measures of treatment effect

In light of the proposed objectives of this review, we used the following types of measurements of treatment effect for the primary studies.

  • Dichotomous data: outcome measures evaluated as binary responses. We summarised results as risk ratios (RRs). This type of data was found for the numbers of exacerbations and adverse events and for reduction in medication use.

  • Continuous data: outcome measures evaluated by numerical quantity. We combined results using the mean difference (MD) for measures using the same scale, or the standardised mean difference (SMD) when different scales were used to evaluate the same outcome. This type of data was found for symptoms and lung function.

  • Counts and rates: may mean that exacerbation episodes are counted twice or more frequently in the same person. We planned to use the risk ratio, as it represents the rate of events in the two groups attained by dividing one by the other; however these data were not found.

  • Time-to-event: use of the hazard ratio as planned to describe the risk ratio of exacerbation based on comparisons of event rates in both groups.

When we found more than one study that analysed the same outcome, we conducted a meta-analysis. All statistical parameters used 95% confidence intervals (CIs) (Deeks 2011).

Unit of analysis issues

We considered the individual participant to be the unit of analysis. In the cross-over design, we included only phase one data to avoid a carry-over effect. If we had encountered cluster-randomised trials, we planned to use the groups randomly assigned as the unit of analysis.

Dealing with missing data

We contacted authors of studies by email when reports did not describe the outcome measures of interest, the process of randomisation or intention-to-treat analysis, and when other necessary data were missing. We sent at least two emails to the corresponding author; if no answer was obtained, we discussed this in the results section of the review.

Assessment of heterogeneity

We would have assessed inconsistencies between studies by using the I2 statistic to describe the extent of statistical variation among study results, if we had found heterogeneity. We would have considered heterogeneity to be substantial when I2 > 50% (Deeks 2011). If we had found substantial heterogeneity among studies, we would have explored this subgroup analysis of study characteristics.

Assessment of reporting biases

Reporting biases can affect the likelihood of publication, and statistically significant results may be selectively reported. It is important that this is assessed because reporting biases may overestimate or underestimate the treatment effect. If mismatches had been identified, we would have contacted the study authors for further information. If necessary, we would have explored the impact of including such studies by conducting a sensitivity analysis. We did not perform a funnel plot asymmetry test because we found a limited number of included studies.

Data synthesis

We would have conducted a meta-analyses if the combination of data had been possible. We would have used a fixed-effect model unless heterogeneity had been substantial (I2 > 50%), in which case we would have chosen a random-effects model. We presented data in forest plot graphics produced by RevMan 5.2. If data combination had not been possible, we would have described the individual studies.

We created Summary of findings for the main comparison by adhering to the methods and recommendations described in Section 8.5 and Section 12 of the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011b; Schünemann 2011) and by using GRADEpro software (GRADEpro 2008). We included the following outcomes: quality of life, number of acute exacerbations, level of severity of disease, lung function, medication usage and adverse events.

Subgroup analysis and investigation of heterogeneity

We planned to conduct subgroup analysis while considering participant, intervention and environmental characteristics.

Participant characteristics
  • Co-morbidities.

Intervention characteristics
  • Type of exercise (swimming (horizontal), hydrogymnastics (vertical)).

  • Frequency of exercise (how many sessions/wk).

  • Intensity: light (1.6 to 2.9 metabolic equivalents (METs)), moderate (3 to 5.9 METs), vigorous (≥ 6 METs).

Environmental characteristics
  • Water temperature and air humidity.

  • Water treatment process (chlorinated vs non-chlorinated).

  • Water depth.

Sensitivity analysis

If we had been able to pool data from included studies, we planned to test studies with limited information to check whether the robustness of the assumptions had influenced review findings. Moreover, we planned to conduct sensitivity analyses by removing studies at high or unclear risk of bias. We also planned to conduct sensitivity analyses to look at the effects of missing data.

Results

Description of studies

See Characteristics of included studies and Characteristics of excluded studies.

Results of the search

See Figure 1. A total of 1719 references were identified from the initial search combining all prespecified databases, handsearching of reference lists, grey literature and trial registers (Figure 1). A total of 1007 references remained after duplicates were removed, of which 953 were removed after titles were screened by two review authors. The remaining 54 references were screened by two review authors on the basis of their abstracts. From these, 48 studies were excluded. Only six studies were identified as potentially relevant, and full-text articles for these were retrieved. Two study authors (Boulet 2005; Fitch 1971) were contacted for more information. The remaining three articles were excluded, and reasons for exclusion have been specified (see Excluded studies). The review authors agreed that three articles fulfilled the study inclusion criteria of this systematic review (see Included studies).

Figure 1.

PRISMA flow diagram.

Included studies

We included three studies involving 136 adults, published between 1998 and 2007: two studies in the English language (Aranđelović 2007; Emtner 1998) and one in Portuguese (Pereira 2005). One study from Sweden (Emtner 1998), one from Serbia (Aranđelović 2007) and one from Brazil (Pereira 2005) met the inclusion criteria. Sample sizes ranged from 32 to 70 participants. Participants had a mean age of between 33 and 36 years. The proportion of female participants varied between 44% and 78%. Asthma was diagnosed on the basis of guidelines-specified criteria in two studies (Aranđelović 2007; Emtner 1998). All studies were RCTs of adults with asthma; intervention groups were provided with water-based exercise, swimming (Aranđelović 2007), gymnastics movements (Emtner 1998) and strength/resistance training (Pereira 2005). The intensity of the water-based exercise programme varied, lasting between 40 and 60 minutes one to five times per week; the length of the programme ranged from one day (one session) to 24 weeks, and moderate- to high-intensity exercises were delivered by a physiotherapist. Three pools were located indoors and were heated. One pool was non-chlorinated (Aranđelović 2007), and in two studies, the water treatment process was not specified (Emtner 1998; Pereira 2005). The comparison group performed land-based exercise in two studies (Emtner 1998; Pereira 2005), and in one study, the comparison group was given usual care medication (Aranđelović 2007). In one study, asthma was specified as persistent, with severity graded as mild (Aranđelović 2007). In another study, asthma was graded as mild/moderate (Emtner 1998), and another study did not specify the criteria for diagnosis; however, study authors specified asthma as persistent and graded it as moderate or severe (Pereira 2005). Participants' regular medication was continued during all three studies. All participants in Aranđelović 2007 were treated with low doses of inhaled corticosteroids and short-acting beta2-agonists (salbutamol); in Emtner 1998, 24 participants were treated with > 400 mg inhaled corticosteroids and long-term beta2-agonists, and eight participants with < 400 mg of inhaled corticosteroids. All participants in Pereira 2005 used exclusively short-acting beta2-agonists. No study specified its primary or secondary outcomes.

These studies met the inclusion criteria of the review; full information on each study is available in Characteristics of included studies. In addition, we provide a comparison of baseline characteristics in Table 1 and a comparison of intervention characteristics in Table 2.

Table 1. Comparison of baseline characteristics of included studies
  1. ATS = AmericanThoracic Society; GINA = Global Initiative for Asthma.

ID/Location/Full publicationn randomly assigned/Withdrawals% femaleMean age (DP)Asthma diagnosisAsthma severity
Aranđelović 2007/Serbia/Yes70/575.433.31 (10.34)GINA criteriaMild persistent asthma
Emtner 1998/Sweden/Yes32/143.736 (10)ATS criteriaMild or moderate asthma
Pereira 2005/Brazil/Yes40/077.533.4 (8.77)Not statedModerate and severe persistent asthma
Table 2. Comparision of intervention characteristics of included studies
  1. FEV1= forced expiratory volume in 1 second; FEV1/FVC ratio; FVC = forced vital capacity; ICS = inhaled corticosteroids; PD20 = provocative dose; PEF = peak expiratory flow.

ID/Location/Full publicationAsthma treatmentWater-based time/frequency per week/n weeks/Pool type/ SupervisionComparison groupFollow-up point in weeks/outcomes in meta-analysis
Aranđelović 2007/Serbia/YesLow doses of ICS and short-acting beta2-agonist salbutamol1 hour/twice a week/24 weeks/indoor heated non-chlorinated/not informed. Included an educational componentControl group with medication (but no educational component)24 weeks/FEV1 (L), FVC (L), FEV1/FVC ratio, PEF (L/s), PD20
Emtner 1998/Sweden/Yes24 participants > 400 mg ICS and long-term beta2-stimulants45 minutes/5 days in the first 2 weeks, then twice a week for 8 weeks/10 weeks/Indoor heated/PhysiotherapistLand-based exercise10 weeks/FEV1 (L), FVC (L), FEV1/FVC ratio, PEF (L/s), PD20
Pereira 2005/Brazil/Masters' dissertationShort-acting beta2-agonists exclusively40 minutes/1 session only (1 day)/Indoor heated/PhysiotherapistLand-based exercise1 day/ FEV1 (L), FVC (L), FEV1/FVC ratio, PEF (L/s)

Excluded studies

Three studies were excluded with reasons (see Characteristics of excluded studies): One study was not an RCT (Boulet 2005); another study analysed exercise-induced asthma (Fitch 1971); and another other study did not include a control group (Hildenbrand 2010).

Risk of bias in included studies

All three included studies had at least three categories judged to be at high risk of bias (Figure 2; Figure 3).

Figure 2.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Figure 3.

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

Allocation

The term randomisation was used in all studies. However, two studies did not explain how randomisation was conducted (Aranđelović 2007; Pereira 2005), so we contacted the study authors; only Pereira 2005 returned a satisfactory explanation of how this was done. Therefore Pereira 2005 was judged to be at low risk of bias, and Aranđelović 2007 at unclear risk of bias. One study had high risk of bias because participants were randomly assigned by odd and even birth dates (Emtner 1998). Allocation concealment was judged as high risk of bias for all three studies (Aranđelović 2007; Emtner 1998; Pereira 2005).

Blinding

Because of the nature of the study interventions, blinding of participants was not applicable; thus we classified all studies as high risk of performance bias. For detection bias, one study did not specify whether the outcome assessor was blinded (Aranđelović 2007), so we judged it as unclear risk of bias. Another study blinded the outcome assessor (Emtner 1998), so we classified it as low risk of bias. In another study, the researcher assessed participant outcomes, so we classified the study as high risk of bias (Pereira 2005).

Incomplete outcome data

One study reported loss of one participant (Emtner 1998), and another study no loss to follow-up (Pereira 2005), so we judged both as being at low risk of bias. Another study reported loss of five participants in the control group, and investigators did not use intention-to-treat analysis, so we classified it as high risk of bias (Aranđelović 2007).

Selective reporting

All study protocols were not available, and some outcome results were not reported in all three studies, so we judged all studies as high risk of bias (Aranđelović 2007; Emtner 1998; Pereira 2005).

Other potential sources of bias

In Aranđelović 2007, no education was given to the control arm (high risk of bias). Emtner 1998 reported baseline imbalance, which may have been related to the quasi-randomised design (high risk of bias). Pereira 2005 used a cross-over design with a washout period of one week, so it is unclear whether washout time was sufficient for exercise; therefore we classified the study as unclear risk of bias.

Effects of interventions

See: Summary of findings for the main comparison Comparison of water-based exercise versus control for adults with asthma

See Summary of findings for the main comparison.

Primary outcomes

First comparison: water-based exercise versus land-based exercise (10 weeks): parallel groups
Quality of life

None of the studies provided data on quality of life.

Exacerbations
Exacerbations leading to a course of oral steroids

No study explored this outcome.

Exacerbations leading to health centre/hospital visits

One study with 32 participants analysed exacerbations leading to health centre/hospital visits (Emtner 1998). In this study, water-based exercise was compared with land-based exercise. Two exacerbations were reported in the water-based exercise group, and one in the land-based group during 10 weeks of intervention. Thus, we are very uncertain of whether a difference in the likelihood of an exacerbation leading to a health centre/hospital visit existed between water-based and land-based exercise (RR 1.65, 95% CI 0.17 to 16.33, P value 0.67).

Second comparison: water-based exercise versus land-based exercise (one session): cross-over design
Quality of life

None of the studies provided data on quality of life.

Exacerbations
Exacerbations leading to a course of oral steroids

No study explored this outcome.

Exacerbations leading to health centre/hospital visits

No study explored this outcome.

Third comparison: water-based exercise + education versus medication (24 weeks): parallel groups
Quality of life

None of the studies provided data on quality of life.

Exacerbations
Exacerbations leading to a course of oral steroids

No study explored this outcome.

Exacerbations leading to health centre/hospital visits

No study explored this outcome.

Secondary outcomes

First comparison: water-based exercise versus land-based exercise (10 weeks): parallel groups
Symptoms

One study with 32 participants analysed general symptoms (Emtner 1998). Study authors used a non-validated questionnaire called "Influence of asthma on everyday life," which is composed of 10 questions measured on a visual analogue scale (VAS) of 10 centimetres. This study did not report a significant difference in asthma symptoms between water-based exercise and land-based exercise (MD 0.20, 95% CI -1.18 to 1.58, P value 0.78).

Lung function

Forced expiratory volume in one second (FEV1)

One study with 32 participants analysed FEV1 (Emtner 1998). Investigators reported a statistically significant difference in FEV1 between water-based exercise and land-based exercise when data were analysed as final values (MD 0.7 L, 95% CI 0.17 to 1.23, P value 0.009). However, baseline imbalance between groups was evident, and the difference in FEV1 was no longer significant in comparisons of change from baseline (MD 0.30 L, 95% CI -0.23 to 0.83, P value 0.27), as shown in Analysis 1.3.

Peak expiratory flow (PEF) (L/min)

One study with 32 participants analysed PEF. In Emtner 1998 (n = 32), researchers did not find a significant difference in PEF between the two groups (MD 26.00 L/min, 95% CI -44.16 to 96.16, P value 0.47).

Use of medication

Only one study mentioned use of medication (n = 32). In Emtner 1998, study authors mentioned that all participants continued with the same medication at the same dosage.

Adverse events

One study with 32 participants reported adverse events. In Emtner 1998, one person in the water group reported skin sensitivity, stopped water-based exercise for three weeks and then was transferred to a land-based group. Thus, considerable uncertainty remains about adverse events in the two groups (RR 2.65, 95% CI 0.12 to 60.21, P value 0.54).

Second comparison: water-based exercise versus land-based exercise (one session): cross-over design
Symptoms

Only one cross-over study with 40 participants reported anxiety symptoms immediately after a single treatment with land-based or water-based exercise (Pereira 2005). Study authors measured the symptom (anxiety) using the State-Trait Anxiety Inventory (STAI), which is composed of 20 items scored on a four-point scale; it was translated and adapted from Portuguese. A decrease in anxiety was noted after both types of exercise, which represented a statistically significant change from baseline for both arms when participants received water-based exercise, and for one arm when land-based exercise was provided. However, no appropriate comparison of the differences between land-based and water-based treatment was reported.

Lung function

Forced expiratory volume in one second (FEV1)

After a single session of exercise, we remain very uncertain about any difference in FEV1 in the first arm of the cross-over study (MD -0.14 L, 95% CI -0.53 to 0.25, P value 0.48).

Peak expiratory flow (PEF) (L/s)

Similarly, after a single session of water-based exercise versus land-based exercise (n = 40), we remain very uncertain about any difference in PEF from the first arm of the cross-over study (MD 23.70, 95% CI -37.18 to 84.58, P value 0.45).

Third comparison: water-based exercise + education versus medication (24 weeks): parallel groups
Symptoms

No study explored this outcome.

Lung function

Forced expiratory volume in one second (FEV1)

In Aranđelović 2007 (N = 65), no significant difference in FEV1 was noted between water-based exercise and usual care medication plus education (MD 0.32 L, 95% CI -0.13 to 0.77, P value 0.16).

Peak expiratory flow (PEF) (L/min)

Aranđelović 2007 included 65 participants divided into water-based exercise and usual care medication plus education groups; the duration of the intervention was 24 weeks, and no significant differences in PEF were reported (MD 40.20 L/min, 95% CI -7.87 to 88.27, P value 0.10).

Subgroup analysis

We prespecified subgroup analysis of participant, intervention and environmental characteristics. Because the included studies used different designs, different types and numbers of exercise sessions and different control groups, we were unable to pool the data and explore subgroup analysis.

Sensitivity analysis

We could not perform sensitivity analysis because of clinical and methodological differences among the included studies.

Discussion

Summary of main results

This review aimed to determine the effectiveness and safety of water-based exercise as an intervention for adults with asthma. When the primary outcomes were analysed, quality of life was not explored before or after intervention in any of the studies, nor was the outcome of exacerbations leading to the use of steroids. Exacerbations leading to health centre visits or to hospitalisations were analysed by one study that compared water-based exercise versus land-based exercise over 10 weeks of exercise; however, very few events were reported, and we remain uncertain about whether differences existed between the groups (Emtner 1998).

In terms of the secondary outcome of symptoms, in Emtner 1998, no significant difference in general asthma symptoms was reported after 10 weeks of exercise.

To assess lung function, we explored FEV1 and PEF. For FEV1, Emtner 1998 found a statistically significant difference favouring water-based exercise over land-based exercise; however, we have to be cautious with these data because baseline imbalance was described among groups, and in analyses of change from baseline, the difference was no longer significant. No significant difference in FEV1 or PEF was seen in either of the other two studies.

The sole study reporting on the outcome of medication use (Emtner 1998) found that all study participants continued to take the same doses after training. One study reported adverse effects (skin sensitivity) in one person in the water-based exercise group (Emtner 1998).

Overall completeness and applicability of evidence

The three included studies randomly assigned 142 participants who commenced the intervention, and overall six participants were lost to follow-up. The number of included studies is small, and the data are too limited to support decision making. All studies evaluated some variable of lung function. An update of a Cochrane review on the effects of exercise on participants of all ages with asthma reported that exercise was well tolerated by study participants and found no evidence of adverse effects on asthma symptoms (Carson 2013). Our review sought to assess water-based exercise specifically for adults with asthma and to summarise the best available evidence.

This review is unable to present strong evidence on the topic. Regarding the safety of water-based exercise, it is important to mention that only one participant in the water-based exercise group had an adverse event of a skin complaint (Emtner 1998). Additionally, some observational studies have suggested potential risks concerning respiratory or allergic disease (Bernard 2009; Font-Ribera 2011; Kohlhammer 2006; Schoefer 2008). It is not possible to establish a cause-effect relationship about exercise performed in an aquatic environment; further studies on this topic are needed.

It is important to mention that the nature of the water-based exercise employed in studies varied, both in intensity (moderate and high) and in frequency (one day to six months), as did asthma severity (mild, moderate and severe). This makes it difficult to envisage a standardised intervention that will allow investigators to understand the effects of water-based exercise. Noting such problems, Hildenbrand 2010 proposed a standard protocol of water-based exercise for adults with asthma, but this intervention has not yet been tested by a randomised controlled clinical trial.

The age groups analysed by all three included studies were very similar; the mean age of participants was 34.23 (SD = 9.7) years. However, these studies examined the effects of exercise, a very complex intervention, on participants with different types of asthma and concluded that exercise is most effective when prescribed on the basis of asthma severity.

Quality of the evidence

The three included studies (Aranđelović 2007; Emtner 1998; Pereira 2005) were generally classified as high risk of bias. All studies analysed had high risk of bias in terms of allocation concealment and selective outcome reporting, which may have made it possible for the trialists to know which participants received which intervention, and this may present a risk of selection bias. Most studies reported only surrogate outcomes. In Aranđelović 2007, no category was classified as low risk of bias. We tried to contact the study author to obtain clarification but received no response.

Emtner 1998 had low risk of bias in blinding of the assessor and in attrition, because the evaluator was a professional who did not provide the intervention or perform the randomisation, and because loss of participants was minimal and was explained. The high risk of selection bias in Emtner 1998 could have impacted the baseline imbalances and could have influenced the intervention effects. Additionally, the high risk of reporting bias could have affected the outcomes presented by the study author (i.e. we are uncertain whether study authors published everything that they measured). In Pereira 2005, the study author provided information by email explaining how randomisation was conducted and that the study did not report sample loss; these were the only categories classified as low risk of bias. Also in Pereira 2005, high risk of bias in terms of allocation concealment could have influenced the selection of participants with asthma of different severity for inclusion in intervention and control groups. In Aranđelović 2007, many factors influenced the classification of high risk of bias, including the following: The asthma education intervention was a confounder in the exercise group, reporting of outcomes was selective and outcome data were incompletely reported.

On the basis of GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria, the quality of evidence for primary outcomes such as exacerbations leading to health centre/hospital visits was classified as very low because of the mode of selection of individuals, the selective reporting and fact that very small numbers of participants were included. For secondary outcomes of lung function (FEV1, PEF), reduction in medication use and adverse effects, the quality of evidence was judged to be very low because of the high risk of bias, as the size and direction of the effect may have been influenced by the small numbers of participants and the high risk of bias in allocation concealment. Clinical variability, different severities of asthma and different exercise intensities among studies have also played an important role in lowering the quality of evidence.

Potential biases in the review process

We used a highly sensitive search strategy (i.e. avoided locating references that were not reports of randomised trials comparing water-based or land-based exercise vs standard therapy). Also, we did not limit the search on the basis of language, date of publication or publication status (grey literature) for the primary studies. All three studies did not register their trials, so it is important to consider this as a potential source of bias. We were unable to combine data in a meta-analysis because of study heterogeneity and limitations. Additionally, we found no ongoing studies in the clinical trial registries.

Agreements and disagreements with other studies or reviews

The conclusions of seven systematic reviews on asthma and exercise—five Cochrane reviews (Beggs 2013; Carson 2013; Dennis 2012; Freitas 2013; Silva 2013) and two non-Cochrane reviews (Eijkemans 2012; Posadzki 2011)—can be compared with the findings of our review

The systematic review of Beggs 2013 included eight trials on swimming for children and adolescents up to 18 years of age. The quality of evidence on outcomes, quality of life and asthma symptoms was judged as low. For the outcomes of emergency department visits, FEV1 and VO2max, the studies were judged as of moderate and high quality. This review concluded that swimming training is well tolerated in children and adolescents with stable asthma and can improve lung function and cardiopulmonary fitness.

Carson 2013 included 21 studies on exercise training for persons with asthma who were eight years of age or older. The quality of evidence was judged as very low or low for all outcomes examined in the 21 studies, and most studies were classified as unclear risk of bias. Despite the limitations, investigators found significant beneficial effects of exercise on oxygen consumption and concluded that exercise "was well tolerated as such, people with stable asthma should be encouraged to participate in regular exercise training, without fear of symptom exacerbation."

Silva 2013 included five studies on inspiratory exercises for adults with asthma. The quality of evidence was judged as very low or low for all outcomes analysed, and selection bias (randomisation and allocation concealment) for all five studies was judged as unclear. Benefits of exercise were found in maximal inspiratory pressure and maximal expiratory pressure. The review author concluded that study results cannot be generalised to children or people with severe asthma, and that the benefits vary according to the type of exercise performed.

Freitas 2013 investigated breathing exercises for adults with asthma; 13 studies were included, and the quality of evidence for all outcomes analysed was classified as very low. Only four of the 13 studies were considered at low risk of bias, and for most of the remaining studies, the risk of bias was judged as unclear. Review authors concluded that breathing exercises are safe and well tolerated for people with asthma. Additionally, the meta-analysis showed positive effects of exercise on quality of life and asthma symptoms.

Dennis 2012 found no RCTs that examined techniques for Alexander chronic asthma.

Two non-Cochrane systematic reviews were identified. Posadzki 2011 analysed yoga exercises for adults with asthma and included RCTs and non- RCTs. Seven studies were included in the review, and two were assessed as low risk of bias. Study authors were unable to summarise the results because of heterogeneity, and the review was inconclusive about the effects of yoga because of methodological limitations and the heterogeneity of primary studies. Eijkemans 2012 conducted a systematic review to assess the benefits of physical activity for patients with asthma; they included 39 studies: 34 cross-sectional and five longitudinal. The review authors evaluated the articles using the Newcastle-Ottawa Scale; 79% were deemed to be of moderate or good methodological quality. The review authors concluded that the level of physical activity is a protective factor in the development of asthma, and that some factors such as age groups, gender differences and sedentary lifestyle are major sources of heterogeneity that must be observed when future studies are planned.

The types of exercise involved in most of the systematic reviews included in this section differed from those examined in the current systematic review. Only one systematic review involved water exercise (swimming), and study participants were of a different age group (children and adolescents).

Authors' conclusions

Implications for practice

The small numbers of participants in the three included studies, the clinical and methodological heterogeneity observed and the high risk of bias noted mean that we are unable to assess the place of water-based exercise in the treatment of patients with asthma.

Implications for research

Randomised controlled trials are needed to assess the efficacy and safety of water-based exercise for adults with asthma. We suggest greater methodological rigour (participant selection, blinding of outcome assessors, reporting of all outcomes analysed and registering of the study protocol) for future research.

Acknowledgements

The review authors wish to acknowledge Emma Welsh, Chris Cates, Emma Jackson and Julia Walters for providing attention and assistance, and Liz Stovold for building the search strategy. We would like to thank the Cochrane Handbook Study Group from the Brazilian Cochrane Centre for providing the opportunity to discuss and explore Cochrane methodology.

Julia Walters was the Editor for this review and commented critically on the review.

Data and analyses

Download statistical data

Comparison 1. Water-based exercise versus land-based exercise (10 weeks): parallel groups
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Exacerbations leading to health centre visits or exacerbations leading to hospitalisations1 Risk Ratio (M-H, Fixed, 95% CI)Totals not selected
2 Symptoms (general symptoms)1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
3 Lung function (FEV1 (L))1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
3.1 Final value1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
3.2 Change from baseline1 Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
4 Lung function (PEF (L/min))1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
5 Reduction in medication use1 Risk Difference (M-H, Fixed, 95% CI)Totals not selected
6 Adverse events1 Risk Ratio (M-H, Fixed, 95% CI)Totals not selected
Analysis 1.1.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 1 Exacerbations leading to health centre visits or exacerbations leading to hospitalisations.

Analysis 1.2.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 2 Symptoms (general symptoms).

Analysis 1.3.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 3 Lung function (FEV1 (L)).

Analysis 1.4.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 4 Lung function (PEF (L/min)).

Analysis 1.5.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 5 Reduction in medication use.

Analysis 1.6.

Comparison 1 Water-based exercise versus land-based exercise (10 weeks): parallel groups, Outcome 6 Adverse events.

Comparison 2. Water-based exercise versus land-based exercise (1 session): cross-over
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Lung function (FEV1 (L))1 Mean Difference (IV, Random, 95% CI)Totals not selected
2 Lung function (PEF (L/min))1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
Analysis 2.1.

Comparison 2 Water-based exercise versus land-based exercise (1 session): cross-over, Outcome 1 Lung function (FEV1 (L)).

Analysis 2.2.

Comparison 2 Water-based exercise versus land-based exercise (1 session): cross-over, Outcome 2 Lung function (PEF (L/min)).

Comparison 3. Water-based exercise + education versus medication only (24 weeks): parallel groups
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Lung function (FEV1 (L))1 Mean Difference (IV, Random, 95% CI)Totals not selected
2 Lung function (PEF (L/min))1 Mean Difference (IV, Fixed, 95% CI)Totals not selected
Analysis 3.1.

Comparison 3 Water-based exercise + education versus medication only (24 weeks): parallel groups, Outcome 1 Lung function (FEV1 (L)).

Analysis 3.2.

Comparison 3 Water-based exercise + education versus medication only (24 weeks): parallel groups, Outcome 2 Lung function (PEF (L/min)).

Appendices

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

Electronic searches: core databases

Database Frequency of search
MEDLINE (Ovid)Weekly
EMBASE (Ovid)Weekly
CENTRALMonthly
PsycINFO (Ovid)Monthly
CINAHL (EBSCO)Monthly
AMED (EBSCO)Monthly

 

Handsearches: core respiratory conference abstracts

Conference Years 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. Search strategy for Cochrane Airways Group Register

#1 AST:MISC1

#2 MeSH DESCRIPTOR Asthma Explode All

#3 asthma*:ti,ab

#4 #1 or #2 or #3

#5 MeSH DESCRIPTOR Water Explode All

#6 MeSH DESCRIPTOR Swimming Pools

#7 water*

#8 aquatic*

#9 immers*

#10 bath*

#11 whirlpool*

#12 pool*

#13 hydro*

#14 #5 or #6 or #7 or #8 or #9 or #10 or #11 or #12 or #13

#15 exercis*

#16 gym*

#17 aerobic*

#18 anaerobic*

#19 breathing*

#20 endurance*

#21 train*

#22 kinesiotherap*

#23 isokinetic*

#24 isometric*

#25 treadmill*

#26 muscle*

#27 muscular*

#28 pilates*

#29 plyometric*

#30 resistance*

#31 stretch*

#32 posture*

#33 movement*

#34 motion*

#35 physiotherap*

#36 physical*

#37 fitness*

#38 sport*

#39 walk*

#40 run*

#41 calisthenic*

#42 MeSH DESCRIPTOR Physical Therapy Modalities Explode All

#43 MeSH DESCRIPTOR Exercise Explode All

#44 MeSH DESCRIPTOR Sports Explode All

#45 MeSH DESCRIPTOR Gymnastics

#46 MeSH DESCRIPTOR Exercise Therapy

#47 #15 or #16 or #17 or #18 or #19 or #20 or #21 or #22 or #23 or #24 or #25 or #26 or #27 or #28 or #29 or #30 or #31 or #32 or #33 or #34 or #35 or #36 or #37 or #38 or #39 or #40 or #41  or #42 or #43 or #44 or #45 or #46

#48 #14 and #47

#49 hydrotherap*

#50 swim*

#51 hydrogymnastic*

#52 aqua-aerobic*

#53 "aqua aerobic*"

#54 aquafit*

#55 dive* or diving

#56 hydrokinetic*

#57 hydro-kinetic*

#58 "Ai Chi"

#59 Halliwick

#60 balneotherap*

#61 MeSH DESCRIPTOR Hydrotherapy

#62 MeSH DESCRIPTOR Swimming

#63 MeSH DESCRIPTOR Balneology Explode All

#64 #49 or #50 or #51 or #52 or #53 or #54 or #55 or #56 or #57 or #58 or #59 or #60 or #61 or #62 or #63

#65 #48 or #64

#66 #4 and #65

(MISC1 = field in the Register where each record is coded for disease, e.g. AST = asthma)

Appendix 3. Additional database search stategies

LILACS via BVS (iaHx interface)

asthma AND Exercise AND (((PT:"Ensaio Clinico Controlado Aleatorio" OR PT:"Ensaio Clinico Controlado" OR PT:"Ensaio Clinico" OR MH:"Ensaios Clinicos Controlados Aleatorios como Assunto" OR MH:"Ensaios Clinicos Controlados como Assunto" OR MH:"Ensaios Clinicos como Assunto") OR ((PT:"Estudo Multicentrico" OR MH:"Estudos Multicentricos como Assunto" OR MH:"Distribuicao Aleatoria" OR MH:"Metodo Duplo-Cego" OR MH:"Metodo Simples-Cego" OR MH:"Grupos Controle" OR MH:"Estudos Cross-Over") AND ((tw:ensaio$ or tw:ensayo$ or tw:trial$ or tw:estudo$ or tw:estudio$ or tw:study or tw:studies) AND (tw:azar or tw:acaso or tw:enmascarado or tw:placebo or tw:control$ or tw:aleat$ or tw:random$ or tw:dobleciego or tw:simpleciego or ((tw:simple$ or tw:single or tw:duplo$ or tw:doble$ or tw:double$) and (tw:cego$ or tw:ciego$ or tw:blind$ or tw:mask$))) AND tw:clinic$)) OR ((tw:ensaio$ or tw:ensayo$ or tw:trial$) AND (tw:azar or tw:acaso or tw:enmascarado or tw:placebo or tw:control$ or tw:aleat$ or tw:random$ or tw:dobleciego or tw:simpleciego or ((tw:simple$ or tw:single or tw:duplo$ or tw:doble$ or tw:double$) and (tw:cego$ or tw:ciego$ or tw:blind$ or tw:mask$))) AND tw:clinic$)) AND NOT (MH:animais OR MH:ratos$ OR MH:camundongo$ OR MH:gatos OR MH:primatas OR MH:caes OR MH:coelhos OR MH:suinos OR PT:"in vitro"))

PEDro

exercise AND Asthma; Swimming AND asthma; Water AND asthma

Google Scholar

asthma* "aquatic exercise" "Randomized Clinical Trial" -child*

SIGLE

asthma AND exercise OR swimming AND water

ICTRP WHO

exercise AND asthma

Contributions of authors

Antonio Jose Grande (AJG) co-ordinated retrieval of papers, identified papers for inclusion, extracted and checked data and wrote the background, methods, results, discussion and conclusion sections of the review.

Valter Silva (VS) participated in retrieval of papers, identified papers for inclusion, extracted and checked data and co-wrote the background, methods, results, discussion and conclusion sections of the review.

Brenda NG Andriolo (BNGA) analysed data, wrote statistical methods, co-wrote results and interpreted the data.

Rachel Riera (RR) co-wrote the background and methods sections and provided a critical review of the existing review.

Sergio Alencar Parra (SAP) co-wrote the background and methods sections and provided a critical review of the existing review.

Maria Stella Peccin (MSP) arbitrated on quality assessment, co-wrote the background and methods and provided a critical review of the existing review.

All authors participated in preparing and approved the revised text for publication.

Declarations of interest

None known.

Sources of support

Internal sources

  • None, Other.

    None

External sources

  • None, Other.

    None

Differences between protocol and review

We deleted the head-to-head comparisons (i.e. swimming vs hydrogymnastics and swimming vs hydrotherapy).

In the protocol, we envisaged three different situations for exacerbations. We still believe they have to be analysed differently; however for this review, we believed it made sense to put all of them together and call them exacerbations.

In the protocol, we included the outcome of use of rescue medications (e.g. short-acting beta2-agonists (SABAs)) or symptom controllers (e.g. long-acting beta2-agonists (LABAs)); however in the review, we decided to include the need for SABAs under the outcome of reduction in medication usage.

We planned to used either OR or RR to analyse dichotomous data, however we decided that using RR was more appropriate. We did not derive number needed to treat to benefit (NNTB).

We deleted the outcome 'level of severity of disease' from the summary of findings table as it was included in the protocol through error.

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Aranđelović 2007

Methods

STUDY DESIGN: parallel-group, randomised, prospective study

LOCATION, NUMBER OF CENTRES: asthmatic patients from departments of the Health Centre, University of Nis

STUDY PERIOD: 6-month programme; twice a week on a 1-hour basis

METHODS OF ANALYSIS: At the beginning and the end of the study, spirometry forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and FEV1/FVC × 100 were recorded using a flow-volume spirometer (Jaeger) according to the recommendations of the European Respiratory Society; a broncho provocative test was performed with a histamine dose of 15 μg, which was then increased by doubling doses until FEV1, measured within 1 minute of histamine inhalation, decreased by 20% or more when compared with baseline FEV1; the dose of histamine causing a 20% decrease in FEV1 (provocative dose (PD20) histamine) was calculated by interpolation of the dose-response curves. The skin prick test was performed to examine atopic status versus a panel of 5 common aero-allergens and was defined as positive if values ≥ 3 mm to 1 or more allergens were reported

STATISTICAL ANALYSIS: not specified

Participants

RECRUITMENT MEANS: patients from the Health Centre, University of Nis

TARGET PARTICIPANTS: adults

N SCREENED: 70 adult asthmatic patients

N RANDOMLY ASSIGNED: 70

N COMPLETED: 65 : 45 in the experimental group and 20 in the control group

GENDER

M = 49; experimental 34, control 15
F = 16; experimental 11, control 5

AGE, years: experimental 33.07 ± 9.81, control 33.55 ± 10.88

ASTHMA DIAGNOSIS CRITERIA: patients with mild, persistent asthma selected according to GINA given documented treatment with low doses of ICS and short-acting beta2-agonists

OTHER
BASELINE DETAILS: age, sex, atopic, smoking status

Interventions

SETTING OF INTERVENTION: Experimental group used an indoor swimming pool with natural warm water without chlorination, located in a recreational spa centre in the vicinity of their home

DESCRIPTION OF INTERVENTION: Experimental group practiced swimming twice a week on a 1-hour basis for 6 months

DELIVERED BY: not informed

TREATMENT PERIOD: 6 months

FOLLOW-UP PERIOD: 6 months

CO-INTERVENTIONS: asthma education within an asthma school, which provided information on therapy, breathing, diet, mental hygiene, smoking, physical activities and quality of life through related courses for experimental groups. Both groups continued treatment with low doses of ICS and short-acting beta2-agonists

Outcomes

LUNG FUNCTION: FVC, FEV1, FEV1/FVC, PEF and BHR

ATOPIC STATUS: atopic, non-atopic

FEV1 BASELINE = control group 3.99 (SD = 0.92) L; experimental group 4.27 (SD = 0.97) L; post-intervention control group 4.01 (SD = 0.7) L; experimental group 4.37 (SD = 0.93) L

PRESPECIFIED: at the beginning of the programme

FOLLOW-UP PERIOD: 6 months after the programme start

Notes

Study author did not supply information

STUDY FUNDING: not stated

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskTerm randomised was used; however the randomisation process was not described
Allocation concealment (selection bias)High riskNo mention was made in the text of how allocation was concealed
Blinding of participants and personnel (performance bias)
All outcomes
High riskBecause of the characteristics of the intervention, participants could not be blinded
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskNo information regarding blinding of those who assessed participants was stated in the text
Incomplete outcome data (attrition bias)
All outcomes
High riskLoss of 5 participants in the control group was described by the study author. Investigators did not use ITT analysis
Selective reporting (reporting bias)High riskProtocol was not available. Study was not registered on a clinical trials registry. Only subrogate outcomes were analysed
Other biasHigh riskAsthma education was restricted to the experimental group; this was a confounding factor

Emtner 1998

Methods

STUDY DESIGN: parallel-group, quasi-randomised, prospective study

LOCATION, NUMBER OF CENTRES: asthmatic patients from the Lung Clinic, Uppsala, Sweden

STUDY PERIOD: 10-week rehabilitation programme; Monday to Friday during the first 2 weeks, period 1; twice a week during the following 8 weeks, period 2

METHODS OF ANALYSIS: Participants underwent the tests described below at the start of the programme and after 2 and 10 weeks. A submaximal 6-minute ergometry test was performed on a cycle ergometer with a mechanical friction load at a constant pedaling rate, attaining a heart rate of 140 to 180 beats/min after 6 minutes. A 12-minute walking test was performed in a hospital corridor. Spirometry was carried out with a body plethysmograph (Jaeger Masterlab body 175,050) for measurement of lung volume and specific airway conductance, and a wedge spirometer (Ohio) was used for recording of flow–volume curves. PEFR was measured with a peak flow meter. The highest value of 3 attempts was used. A methacholine provocation test was carried out to measure airway reactivity, expressed as the amount of inhaled methacholine required to cause a fall of 20% in FEV1. Three different questionnaires were administered, with questions concerning physical exercise, effects of asthma on everyday life and participants' experiences. Answers were given on a 10-cm visual analogue scale (0 to 10 cm), on which 0 indicates the worst value and 10 the best. The number of emergency department visits for acute asthmatic attacks during the 10 weeks before the start of the rehabilitation programme and the 10 weeks after the start of the programme was recorded. A training log was kept by each participant to record the frequency and intensity of training and perceived exertion after each exercise session. A diary was kept by each participant. Participants were asked to record their asthma symptoms on a 4-graded scale every evening during the 10-week programme

STATISTICAL ANALYSIS: Data were analysed for statistically significant differences between groups using the unpaired t-test (parametric data) and Mann-Whitney’s U-test (non-parametric data). One-factor analysis of variance for repeated measurements (Fischer PLSD) was used for parametric data, and Friedman’s test was used for non-parametric data. A paired t-test (parametric data) and the Wilcoxon signed-rank test (non-parametric data) were used for comparison between values obtained 10 weeks before and at the start, and between those obtained at the start and after 10 weeks

Participants

RECRUITMENT MEANS: All were outpatients from the Lung Clinic, Uppsala, Sweden

TARGET PARTICIPANTS: adults

N SCREENED: 32 adult asthmatic patients

N RANDOMLY ASSIGNED: 32

N COMPLETED: 31: 17 water group and 14 land group

GENDER

M = 18; water 9, land 9
F = 14; water 9, land 5

AGE, mean, years: land 38 ± 12, water 34 ± 8

ASTHMA DIAGNOSIS CRITERIA: (1) chronic well-controlled asthma (according to ATS) of mild or moderate severity, (2) FEV1% > 75 after inhalation of a beta2-agonist and (3) no concomitant disease

OTHER
BASELINE DETAILS: age, gender, physical condition, baseline spirometry and reversibility

Interventions

SETTING OF INTERVENTION: for land group: gymnastic hall at room temperature of 22°C and relative humidity of 20% to 30%; for water group: indoor swimming pool with water temperature of 33°C at room temperature of 24°C and relative humidity of at least 60%

DESCRIPTION OF INTERVENTION: period 1, 2 weeks, 5 days-a-week training session on land or in the pool (hydrogymnastics) for 45 minutes; daily theoretical lessons in anatomy, physiology, pathophysiology, medication or physical training; and daily practical sessions on techniques for inhalation, breathing, relaxation or incontinence. Period 2, 8 weeks, 2-days-a-week training session on land or in the pool for 45 minutes. Each training session, whether on land or in water, started with a warming-up period (15 minutes) followed by arm and leg exercises, walking and low-intensity jogging. Exercise continued with interval training, comprising five 2-minute periods of intensive exercise separated by eleven 2-minute periods of low-intensity exercise (total 16 minutes). These periods of interval training consisted of varied repetitive large muscle, dynamic exercises with a target pulse rate of 80% to 100% of maximal intensity. A cooling-down period (7 minutes) and stretching exercises (7 minutes) completed the 45-minute session

DELIVERED BY: All training sessions and practical sessions were led by 1 of 2 physiotherapists; the theoretical sessions were led by a physiotherapist, a nurse or a physician

TREATMENT PERIOD: 10 weeks

FOLLOW-UP PERIOD: 10 weeks

CO-INTERVENTIONS: Medication was kept constant during the study period

Outcomes

FEV1, PEF, heart rate, walking distance, breathing rate. Questionnaire measurements (made by study authors): emergency department visits, medication use, missing workdays, asthma symptoms, perceived exertion

FEV1 BASELINE = land group 2.8 (SD = 0.8) L; water group 3.2 (SD = 0.8) L; post-intervention land group 2.6 (SD = 0.7) L; water group 3.3 (SD = 0.8) L

PRESPECIFIED: 10 weeks before and at the start of the programme

FOLLOW-UP PERIOD: 2 weeks and 8 weeks after the programme start

Notes

Study author supplied information regarding randomisation and allocation

STUDY FUNDING: Swedish Heart-Lung Foundation, Stockholm; Heart and Lung Patients National Association, Stockholm; Bror Hjerpstedt Foundation and Lilly and RagnarA° Kerhamn Foundation, Uppsala

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)High riskRandom sequence was generated by odd and even days of birth
Allocation concealment (selection bias)High riskAllocation was in accordance with date of birth
Blinding of participants and personnel (performance bias)
All outcomes
High riskBecause of the characteristics of the interventions, participants could not be blinded
Blinding of outcome assessment (detection bias)
All outcomes
Low riskResearcher who assessed participants was blinded to the intervention
Incomplete outcome data (attrition bias)
All outcomes
Low riskLoss of 1 participant in the water group as the result of skin sensitivity was reported; participant completed the exercise during remaining weeks on land
Selective reporting (reporting bias)High riskProtocol was not available. The study was not registered on a clinical trials registry
Other biasHigh riskBaseline imbalance may be related to sequence generation

Pereira 2005

  1. a

    ATS: American Thoracic Society; BHR: bronchial hyperresponsiveness; FEF: forced expiratory flow; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; GINA: Global Initiative for Asthma; ICS: inhaled corticosteroids; ITT: intention-to-treat; MEP: maximal expiratory pressure; MIP: maximal inspiratory pressure; PD20: provocative dose 20; PEF: peak expiratory flow; PEFR: peak expiratory flow rate; PLSD: protected least significant difference; SD: standard deviation; STAI: State-Trait Anxiety Inventory.

Methods

STUDY DESIGN: cross-over group; randomised, prospective study

LOCATION, NUMBER OF CENTRES: Physical Therapy Clinic, therapeutic swimming pool at City University of Sao Paulo (UNICID)

STUDY PERIOD: October 2003 to December 2004

METHODS OF ANALYSIS: questionnaires: asthma symptoms and exacerbations; Beck Depression Inventory; quality of life questionnaire for asthmatic patients; State-Trait Anxiety Inventory (STAI); breathing discomfort for adults with asthma. Cirtometry (axillary, xiphoid, umbilical) with measuring tape; strength of respiratory muscles (MV-120 manometer); pulse oximeter (model 9500, Nonin Medical Inc; Spirometry Vitalograph 2120) (FVC, FEV1, FEV1/FVC, PEF and FEF 25% to 75%); peak flow meter

STATISTICAL ANALYSIS: descriptive statistics for all variables plus Kolmogorov Sminoff for normality and Levene for homogeneity of variance. For comparisons, student t-test was used

Participants

RECRUITMENT MEANS: interest list, advertisement in train station and newspaper, last 3 years, asthmatic patients from Sao Paulo Clinics Hospital

TARGET PARTICIPANTS: adults 18 to 50 years of age

N SCREENED: 40 adult asthmatic patients

N RANDOMLY ASSIGNED: 40

N COMPLETED: 40: 20 water group and 20 land group

GENDER

M = 9; water 5, land 4
F = 31; water 15, land 16

AGE, years: water group 34.75 ± 8.32, land group 32.05 ± 9.23

ASTHMA DIAGNOSIS CRITERIA: inclusion criteria: mild and severe asthma for at least 5 years; use of beta2-agonists of short action; age between 18 and 50 years.

Exclusion criteria: smokers or ex-smokers for less than 5 years; response lower than 12% and 200 mL FEV1 after use of bronchodilator; 40% < FEV1 > 80% estimated; pregnancy; airways infection in the past 30 days; associated diseases (pulmonary and extrapulmonary); participation in any other physical activity aimed at pulmonary rehabilitation

OTHER
BASELINE DETAILS: asthma classification, age, gender, weight, height, skin colour, rhinitis, sinusitis, dermatitis, smoking status, practice of physical activity

Interventions

SETTING OF INTERVENTION: for land group: exercises conducted on land; for water group: swimming pool with water temperature of 35°C

DESCRIPTION OF INTERVENTION: Study was composed 1 session of water-based exercise and 1 session of land-based exercise, crossed-over after 7 days of washout. Water-based exercise lasted 40 minutes. Exercise protocol was divided into the following: exercise for thoracic mobility (10 minutes); muscular strength of expiratory muscles (10 minutes); resistance training for inspiratory muscles (10 minutes); and self-stretching of inspiratory muscles (10 minutes); each exercise was performed 10 times. Land-based exercise had the same protocol of exercises. After the intervention, both groups rested 10 minutes on land and proceeded to assessment

DELIVERED BY: researcher

TREATMENT PERIOD: 1 day. 1 session in the water and 1 session on land

FOLLOW-UP PERIOD: finished after last session

CO-INTERVENTIONS: short-acting beta2-agonists kept constant during study period

Outcomes

SIGNS AND SYMPTOMS: depression and anxiety (depression score; anxiety score); quality of life (physical limitation domain, frequency and severity domain; adherence domain, socioeconomic domain, psychosocial domain); degree of respiratory discomfort; forced expiratory volume in 1 second (FEV1); peak expiratory flow (PEF); maximal inspiratory pressure (MIP); maximal expiratory pressure (MEP); cirtometry (axillary, xiphoid, umbilical)

FEV1 BASELINE = land group 2.12 (SD = 0.69) L; water group 1.83 (SD = 0.62) L; post-intervention land group 1.82 (SD = 0.56) L; water group 1.68 (SD = 0.69) L

PRESPECIFIED: tested before and after each session of the intervention

FOLLOW-UP PERIOD: every session

Notes

Study author supplied information regarding randomisation and allocation

STUDY FUNDING: not declared

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskThe study was randomised. We contacted the author who explained that randomisation was done by drawing numbered pieces of paper from a container.
Allocation concealment (selection bias)High riskThis was not possible because the author conducted the assessments and the randomisation, so the concealment was not adequate.
Blinding of participants and personnel (performance bias)
All outcomes
High riskDue to the characteristics of the intervention participants could not be blinded.
Blinding of outcome assessment (detection bias)
All outcomes
High riskThe researcher who assessed the patients have also conducted the intervention.
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo loss to follow up. The flow of patients were clear from baseline through the end.
Selective reporting (reporting bias)High riskProtocol not available. The study was not registered on Clinical Trials Registry. The author did not present some outcomes such as: Quality of life global measure, she presented only the domains; FVC; FEV1; FEV1/FVC; PEF; FEF 25% to 75%; the author did not present the comparisons and she claimed not to be relevant.
Other biasUnclear riskThe study design was a cross-over with a washout period of 1 week. Since the aim of the study was assess the acute effects after intervention, it is unclear if it was enough time of washout for exercise.

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Boulet 2005Although the study was randomised, we contacted the study author, who explained that most participants were not given a diagnosis of asthma
Fitch 1971The study analysed exercise-induced asthma
Hildenbrand 2010The study did not include a control group