Exercise as it relates to Disease/Controlling Young Adult Asthma Through Childhood Exercise

The following Wikibooks page is an analysis of “low physical fitness in childhood is associated with the development of asthma in young adulthood: the Odense schoolchild study” by Rasmussen et al. (2000)

What is the background to this research?
Exercise has been shown to enhance lung growth in a study on animals, but there is no evidence that it does the same for humans. However, in some lung diseases, exercise has been proven to be vital in rehabilitation. Commonly in asthmatics, exercise is found to trigger symptoms causing individuals to reduce the amount of exercise they are doing. Studies of asthmatics have shown that improving physical fitness has been associated with reduced symptoms and reduced medication use, indicating that children who have increased physical fitness may have improved lung function so they are protected from asthma developing later in life. Based on this, the study investigated whether physical fitness in childhood would impact on the development of asthma in puberty.

Where was this research from?
The research was conducted on a community of Odense School children, completed by the department of respiratory diseases at the Odense University hospital, Denmark. The research is supported by nongovernment organisation’s including the Danish Lung Association and Danish Medical Research, the authors have not disclosed of known bias or conflict of interest.

What kind of research was this?
The study conducted was a Multi-Disciplinary Epidemiological study of a community based cohort, involving 1,369 school children. Data was collected through a series of physical tests and questionnaires; it was later analyzed though statistical analysis. Subjects were on average 9.7 years old when research initially began and all were followed for 10.5 years. This type of research produces results as interpreted by the authors stated as facts based on the cohort. It can then be used as a general interpretation of likely outcome but is not indicative of international population health. Further research should investigate children from multiple areas rather than a specific area and cohort.

What did the research involve?

 * 1369 school children, first investigated in their third grade (8.5-11years old)
 * 473 subjects with asthma, asthma related symptoms or a fall in FEV1 >10% after exercise in childhood were excluded
 * 896 non-asthmatics were involved in initial testing based on exclusions, and 757 were investigated at follow up

Pulmonary function test


 * Lung function was tested using McDermott bellows spirometer in 1985 and a pneumotachograph in 1996
 * Subjects were encouraged to push themselves to maximal effort for 5 sets of 3 minutes on an electrically braked ergometer cycle, with workload increasing every 3 minutes. Subjects were considered to have reached maximal effort when their heart rate reached 85% of estimated maximal heart rate (220-age in years).
 * At follow up a methacholine provocation test was performed using an inhalation-triggered dosimeter. The first aerosol is a dilutant followed by doubling concentrations of methacholine. Response was measured in FEV1

Questionnaire: Participants were asked questions based on if they had experienced asthma like symptoms, family history of asthma, smoking and allergic rhinitis as well as if the participants had experience chest related illness, any fever and wheezing

What were the basic results?

 * Of the initial 757 asymptomatic children, 51 had been diagnosed with asthma at the follow up
 * The individuals that developed asthma had lower average physical fitness than their peers
 * 3.63 vs 3.89 Wkg-1 for males
 * 3.17 vs 3.33 Wkg-1 for females
 * Physical fitness was separated into 5 quintiles; a falling rate of new asthma cases was seen as physical fitness increased
 * Risk of development of asthma during adolescence was reduced 7% by increasing maximal work load with 1Wkg-1

Limitations

 * Participants were selected as a random baseline population, however all participants were from the same school and same residential area only showing that results may be correct within this area not for a greater population.
 * The research looks at a cohort of children in the third grade which only accounts for a very limited age range, as they are only tested at 2 time points. Thus results may be indicative for children of 8.5–11 years old but not necessary for all children
 * Using different equipment to test pulmonary function may result in less reliable results.
 * Participants self-reported answers to the questionnaires with the help of parents so answers could be over or underestimated or misinterpreted

What conclusions should be taken away from this research?
The study shows that there is a very weak relationship between physical fitness in childhood and asthma in adolescence. It does however show that there is a correlation between low physical fitness and an increased risk of asthma when compared to subjects with high physical fitness. This data only relates however to a specific age group within a specific population and may not correlate to a wider population or age group. For this research to be more reliable further research should be completed looking at wider age groups and multiple population groups rather than a small cluster.

Practical Advice
As the authors stated, intense physical activity may impact a child one of 2 ways, it may improve physical fitness and protect against asthma or it may trigger symptoms . From this, any child wishing to partake in high intensity exercise when they already have asthma should seek medical advice from a health professional beforehand. Additionally, individuals should be aware of the impact of not exercising on cardiovascular health if they choose not to exercise.