Exercise as it relates to Disease/The effects of different exercise programs on asthma control in children

This is a critique of the article: Chris Carew & Des W Cox (2018) Laps or lengths? The effects of different exercise programs on asthma control in children, Journal of Asthma, 55:8, 877-88. .

The critique was written as an assignment in the unit; Health, Disease and Exercise at University of Canberra, 2019

Background to Research
In Australia, approximately 12.3% of boys and 9.5% of girls under the age 15 are living with asthma. Asthma is defined as chronic inflammation of the airways and symptoms can range from mild to very severe. Examples of common symptoms include shortness of breath, wheezing, tightness in the chest and in extreme circumstances death. 21.8% of asthma sufferers between 12 and 25 report missing work, study or school due to asthma related symptoms. This not only impacts the lives of individuals diagnosed with the condition but has an estimated cost to the economy of 28 billion dollars per year. The prevalence of asthma diagnosis is gradually increasing and is generally higher in both Indigenous and lower socioeconomic areas.

''Table 1. Prevalence of Asthma amongst Young Australians''

With the continually inclining rates of asthma amongst children in Australia, it is important to develop effective management strategies for the condition. Previous studies have shown that swimming can improve lung function and reduce symptoms in asthma sufferers. The purpose of this study was to determine if swimming could be more beneficial for lung function and asthma symptoms than football or basketball.

Research
This article was published in the Journal of Asthma in 2017. Dr. Des Cox, co-author of the study, graduated from medicine in 2011 and currently works as the Head of Respiratory Department at Our Lady’s Children Hospital, Dublin, Ireland. His research interests encompass wheezing disorders and Cystic Fibrosis in children which is the focus of his current longitudinal study. He co-wrote this paper with student Chris Carew who is studying medicine at University College Dublin.

Cox and Carew designed a randomized control trial in which the effects of 3 different sports were compared to a control group. 41 children between the ages of 9 and 16 with mild to moderate asthma diagnosed by a doctor were randomly assigned to a swimming, basketball, football or control group. Children with severe asthma were excluded from the study.

Method
The study included a 6-week intervention in which participants took part in their respective sport for 40 minutes once a week. Session programs were designed by the Dublin City University Human Health and Performance Department. To ensure consistency across all sports each session was designed to have the same energy cost. This was estimated by calculating the metabolic equivalent (METs) for each session. Metabolic equivalents are a practical way of prescribing exercise intensity but do not consider individual differences in resting metabolic rate and therefore are only an estimate of energy cost. Measures including heart rate or perceived rate of exertion were not recorded throughout the training program.

Pre and post spirometry tests were used to measure the success of each intervention. Spirometry tests are the most accurate way of assessing asthma severity and consider multiple variables to assess overall lung function. Participants also recorded readings from a peak flow meter each morning and night to monitor gradual changes in lung function. Peak flow meters provide an indication of how narrow an individual’s airways are by measuring the peak speed at which air can be exhaled. They are a practical way of monitoring asthma severity but are considered to be less accurate than a spirometry test.

Qualitative data about symptoms was collected by giving each participant an asthma diary which was filled out at regular intervals throughout the intervention. Each participant also completed an exit survey which collected data on how symptoms had changed over the 6 week period.

In total the participants completed 6 sessions that were 40 minutes in duration. Designing an intervention with a longer duration or greater frequency of sessions may have produced greater physiological adaptations and more robust results. Although the energy expenditure of each session was estimated during the design process this could have been monitored throughout the intervention by using heart rate monitors and session RPE. Both these methods have been shown to give a reliable indication of exercise intensity. Collecting data on the exercise intensity of each session would have reduced error and improved the reliability of the results. Any additional physical activity the participants engaged in should have also been measured in a diary. Highly sedentary or highly active participants may have responded differently to the intervention and therefore influenced the results.

Spirometry Readings
Across all sports the only statistically significant improvement across all spirometry readings was forced vital capacity (FVC) when compared to the control group. All sports showed similar improvement with basketball being marginally ahead of swimming and football. Swimming also showed a statistically significant improvement in peak expiratory flow (PEF). In all sports improvement was also seen in forced expiratory volume (FEV1) and FEV1/ FVC ratio, however findings were not statistically significant. In regards to individual expression of symptoms these findings may still hold clinical significance. The control group showed no improvement in any spirometry readings.

Peak Flow
Despite the no significant change in forced expiratory volume, peak flow measurement improved across all sports. The swimming group experienced the greatest improvement (11.3%) followed by basketball (8.1%) and then football (5.7%). Peak flow declined by 3% in the control group.

''Table 2. Change in Spirometry Readings and Peak Flow''

Asthma Diary and Survey
The exit survey found that 77% of participants in the swimming group reported reduced asthma symptoms, followed by 37.5% of the basketball group and 25% of the football group. 0% of participants in the control group reported an improvement in symptoms. 100% of the swimming group reported an increase in general well-being compared to 50% from the basketball group, 62,5% of the football group and 9% of the control group

Conclusions
For children diagnosed with asthma swimming appears to be a superior sport for improving lung function and reducing the presence of symptoms. Swimming increased forced vital capacity and showed the greatest improvement in peak flow making it the most efficient strategy to improve lung function.

Whilst the study places emphasis on swimming producing the greatest benefit for lung function, it can be concluded that all sports resulted in a significant improvement compared to the control group. As energy expenditure was not recorded during the intervention the results are dependent on the estimations of metabolic equivalents being accurate. It is possible that swimming sessions had a greater physiological demand than the other groups.

Based on the qualitative data swimming is significantly more successful in reducing the presence of asthma symptoms and improving general wellbeing. Basketball and football still showed a substantial improvement compared to the control group. Due to the short duration of this study no conclusions can be made regarding how long the benefits of the intervention will be sustained.

Practical Advice
It is likely that for children diagnosed with asthma swimming will produce greater benefits compared to basketball or football. Swimming is the most effective at improving lung function, reducing the presence of symptoms and improving well-being. The prevalence of asthma is higher in Indigenous lower socio economic populations where swimming may be less accessible to children due to cost, location and swimming ability. It is important to note that all sports produced beneficial effects when compared to no sport. Children suffering with asthma should try and participate in sport a minimum of once per week to manage symptoms. If swimming is accessible this may be the best option due to the associated benefits however any sport appears to be better than none.

Further Research
Further information can be found at the following resources:


 * Asthma Statistics in Australia


 * Asthma and Lung Function Tests


 * Benefits of Swim Training on Children with Asthma


 * Effects of Swimming Training on Children with Asthma