Exercise as it relates to Disease/Does physical activity level contribute to asthma?

This is an analysis of the journal article, “Asthma and physical activity - A population based study results from the Swedish GA2LEN survey” by Jerning, C, et. al, 2013.

Background

Briefly, asthma is a condition that affects the airways in the human body. These airways in the lungs are sensitive and react/constrict to triggers that can set off their asthma, making it hard to breathe. Asthma is a chronic disease that has no cure but has treatment options available.

A Swedish study follows on previous research stating that asthma is commonly found to have a link with physical inactivity. A report and study is developed to identify the relationship between high levels of physical activity and asthma. The base of the study is that there is a high prevalence of elite athletes that suffer from asthma or in particular, ‘exercise induced asthma’.

Research

Where Research Originated From

The research was conducted in the country of Sweden. 25,610 individuals in Sweden completed a postal questionnaire. This questionnaire was part of the Global Allergy and Asthma Network (GA2LEN) survey in 2008. The survey was sent to randomly chosen subjects in the age’s 16–75 years.

Kind of Research

This research involved a self-completed survey that looked closely at physical activity levels and its correlation with asthma within individuals. The study defined asthma as having an asthma attack during the previous 12 months, or they had been using asthma medication in the previous 12 months also. Not only did it look at physical activity and asthma, it identified other comorbidity factors such as rhinitis, eczema, asthmatic symptoms and conditions, smoking and certain work exposures.

The participants were asked how often and for how many hours a week they were physically active. The research distinguished the levels of physical activity and the percentage of those that had asthma at different physical activity levels. The participants were asked their estimation of physical activity levels by how often and for how many hours a week they exercised to a point that they got out of breath or became sweaty. Based on evidence the participants were divided into four groups, from physically inactive to vigorously physically active. Asthma was determined by the levels of wheeziness, tightness in chest and occurrences that disallowed them from breathing properly.

Basic Results

There was no difference in being physically inactive or active in subjects with or without asthma (57% vs. 58%). The prevalence of asthma within the population studied was 7.1%. The group with asthma reported a higher proportion of females (61.1%), high levels of rhinitis, obesity, and hypertension compared to the group without asthma.

Characteristics of the Study Population (%)
	No Asthma (n = 23,780)	Asthma (n = 1830)
Gender
Male	46.1	38.9
Female	53.9	61.1
BMI
<20	8.4	7.5
20-25	51.2	46.5
>25-30	31.0	30.4
>30	9.4	15.6
Co morbidities
Rhinitis	20.8	63.0
Hypertension	12.8	14.6
Diabetes	3.0	4.1

The primary results disclosed that those subjects continuously reaching levels of vigorous physical activity had higher levels of asthma (6.7% vs. 4.8%) compared to non-asthmatics. It is more important to note that these results still remained the same after adjustments for gender, age, group, BMI, smoking and rhinitis were taken into consideration.

Characteristics of the Study Population (%)
	No Asthma	Asthma
Physically Inactive
	18.8	16.1
Slightly Physically Active
	39.6	40.5
Moderately Physically Active
	36.8	36.7
Vigorously Physically Active
	4.8	6.7

Interpretation of Results

The researchers established from the results that those subjects with asthma were found to participate in more vigorous physical activity compared to non-asthmatics. Establishing links with other literature that describes the association between increasing respiratory symptoms and vigorous levels of physical activity.

Research Conclusions

Vigorous Exercise

From these results it can be said that vigorous levels of physical activity can develop some form of exercise-induced asthma. Those that trained at this level were found to have a greater prevalence of asthma compared to non-asthmatics. These results are relevant as vigorous levels of physical activity were found to damage and cause inhibition of the airways within the body, triggering dehydration of the mucosa leading to epithelial damage.

Environmental Conditions

Bronchiole Constriction triggered in Asthma

Critically discerning these results it can be said that there are other factors to why asthma is more prevalent in a vigorous physical activity setting. Those that train at this level are exposed to longer, harder and more intense bouts of exercise, which in turn require more of the body’s airways and lungs. Factors such as a warm up were not taken into consideration, which can drastically reduce exercise-induced asthma at this level. Aspects such as time of year and the environmental stresses such as pollen and cold air that trigger asthma were not taken into account. Where people decide to exercise and the environment they are in can drastically increase the prevalence of asthma. This is extremely relevant as those individuals who train at these levels are the ones who will more than likely be exposed to environmental factors as they exercise more often.

Overestimation

It is important to note that this study was self reported which can overestimate certain results. To develop a more specific, detailed and succinct study, greater information needs to be utilized, such as detailed levels of exercise performed by the subjects. Although saying that, as this study contained nearly 30,000 subjects, it is more practical to gain information through a self-report.

Implications of Research

Vigorous physical activity has been shown to develop exercise-induced asthma. Through studies and results it is found that it can damage and harm airways and lungs. What is unclear is the relationship between this vigorous physical activity and sedentary behavior. Clearly and undoubtedly physical activity is of greater benefit to an individual compared to physical inactivity. It provides the benefits of better health through the reduced risk of diseases such as cardiovascular, hypertension and obesity. Subsequently, it is important to understand that physical activity and its high levels of vigorous activity far outweigh the negative consequences of not being physically active at this level. It is therefore not a reduction of activity at this level that should be prescribed but treatment and prevention to allow individuals to be physically active at this level, ultimately lessening asthmatic events.

Further reading

For further information on asthma:

National Asthma Council Australia http://www.nationalasthma.org.au/theasthmaexperts

The New England Journal of Medicine http://www.nejm.org/medical-research/asthma

Asthma Foundation Victoria http://www.asthma.org.au

Australian Asthma Handbook http://www.asthmahandbook.org.au/management/children

Better Health Channel http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Asthma?open