Key message: swimming training is well tolerated in children and teens with asthma and increases physical fitness and lung function.  However, it is not known whether this is better and/or safer than other types of physical activity.

We’re putting the spotlight on asthma today. It’s World Asthma Day and the Cochrane Airways Group has just published a new review on swimming training for asthma. World Asthma Day aims to spread the message “you can control your asthma” and this year activity organizers are being encouraged to complete the sentence “It’s time to…” So does this new review suggest that we could finish that sentence with “swim”?

Eight randomizedRandomization is the process of randomly dividing into groups the people taking part in a trial. One group (the intervention group) will be given the intervention being tested (for example a drug, surgery, or exercise) and compared with a group which does not receive the intervention (the control group).   controlled trialsA trial in which a group (the ‘intervention group’) is given a intervention being tested (for example a drug, surgery, or exercise) is compared with a group which does not receive the intervention (the ‘control group’). (RCTs) were included in the review, with 262 people aged five to eighteen years, who had stable asthma ranging from mild to severe. One RCT evaluated a programme of 30 minutes swimming six times a week; the rest involved swimming from 30 to 90 minutes two to three times a week, for six to twelve weeks. Swimming training was compared with golf in one studyAn investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. and ‘usual care’ in the other studies.

What did they find?

• No difference between groups for the primary outcomesOutcomes are measures of health (for example quality of life, pain, blood sugar levels) that can be used to assess the effectiveness and safety of a treatment or other intervention (for example a drug, surgery, or exercise). In research, the outcomes considered most important are ‘primary outcomes’ and those considered less important are ‘secondary outcomes’. of interest: quality of life (one studyAn investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. of 50 people, swimming compared with golf), asthma control, asthma exacerbations or use of corticosteroids
• Swimming training had a clinically meaningful effect on exercise capacity compared with usual care
• Swimming training was associated with small improvements in resting lung function tests
• There were no adverse effects on asthma control

How good was the evidence and what are the gaps?

• The strength of the evidence (using the GRADE criteria) is low for quality of life and asthma control, moderate for urgent asthma visits to a doctor or lung function, and high for exercise capacity
• DataData is the information collected through research. were limited – only a small number of participants overall and 42 withdrew early
• The 3 RCTs with high withdrawal rates were rated as being at high riskA way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of biasAny factor, recognised or not, that distorts the findings of a study. For example, reporting bias is a type of bias that occurs when researchers, or others (e.g. drug companies) choose not report or publish the results of a study, or do not provide full information about a study.; the other studies were rated as being at low riskA way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of biasAny factor, recognised or not, that distorts the findings of a study. For example, reporting bias is a type of bias that occurs when researchers, or others (e.g. drug companies) choose not report or publish the results of a study, or do not provide full information about a study.
• Swimming pool chlorination status was not reported in 4 studies; no studies reported bronchodilator use or time off school or work
• The reviewers’ attempts to obtain missing dataData is the information collected through research. were unsuccessful
• Studies with longer follow-up periods are needed to determine long term effects

Last year, a Cochrane review evaluating evidence on any sort of physical training for asthma found that it brought short-term improvements in fitness and that, as with swimming, it was well tolerated by people with stable asthma and should be encouraged.

What this review can’t say is whether swimming is better, or safer, than other forms of physical training. But it seems reasonable to say that “it’s time to get active” and if you like to swim then you can enjoy the benefits without fear of aggravating your symptoms. If you are on Twitter and want to follow tweets from World Asthma Day, the hashtag is #WAD2013.

Links:

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 ReviewsIn systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. 2013, Issue 4. Art. No.: CD009607. DOI: 10.1002/14651858.CD009607.pub2.

Cochrane summary and podcast of this review http://summaries.cochrane.org/CD009607/swimming-training-for-asthma-in-children-and-adolescents-aged-18-years-and-under

Carson KV, Chandratilleke MG, Picot J, Brinn MP, Esterman AJ, Smith BJ. Physical training for asthma. Cochrane Database of Systematic ReviewsIn systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. 2013, Issue 9. Art. No.: CD001116. DOI: 10.1002/14651858.CD001116.pub4.

Cochrane summary and podcast of this review http://summaries.cochrane.org/CD001116/physical-training-for-asthma

Swimming improves fitness in children with asthma BMJ 2013;346:f2714

This page was last updated: 31 March 2014