posted on 2013-06-24, 15:06authored byAishwarya Kumar
Asthma is a chronic inflammatory disease characterised by reversible airflow obstruction.
Based on the relationship between a lack of exercise and chronic diseases, the latest
guidelines from the Department of Health (DH) recommend physical activity across the
whole population (DH, 2011). Exercise Induced Bronchoconstriction (EIB) is a ‘sub-type’ of
asthma which affects approximately 90% of all individuals with asthma and an additional
10% of the healthy normal population (ATS/ACCP, 2003; Anderson & Kippelen, 2012);
thus, EIB may be an important limiting factor for physical activity and an important ‘barrier
to exercise’ for a number of individuals.
Asthma is identified primarily by the occurrence of symptoms (wheezing breathlessness
and dyspnoea), peak expiratory flow rates (PEF) and spirometry (Pulmonary Function
tests – PFT). The current spirometry guidelines for the characterisation of asthma include
a fixed criteria for the ratio between forced expiratory volume in one second and forced
vital capacity (FEV1/FVC) (Miller et al., 2005b). This fixed criteria approach lacks specificity
and is likely to misdiagnose approximately 20% of patients (Miller et al., 2011). The
American Thoracic Society (ATS) and the European Respiratory Society (ERS) guidelines
have acknowledged these concerns and have issued position statements for the use of a
different approach using a ‘lower limit of normality’ (LLN) derived from a matched healthy
population (Miller et al., 2009). Based on the fixed criteria, it has been shown that there is
under diagnosis of participants with mild-moderate symptoms participants in the younger
age group (Cerveri et al., 2009; Hansen et al., 2007; Miller et al., 2011; Roberts et al.,
2006; Swanney et al., 2008).
The currently available pharmacological therapies for asthma and EIB are effective
(corticosteroids and bronchodilators), however long-term usage of these medications is
associated with issues of tachyphylaxis and negative side effects (Barnes, 2010; GINA,
2011). There is some evidence from observational and intervention studies to suggest a
beneficial effect of fish oil (comprising of omega-3 (n-3) polyunsaturated fatty acids
(PUFAs)) in inflammatory diseases, (specifically asthma). Marine based n-3 PUFA have
therefore been proposed as a possible complimentary/alternative therapy for asthma. The
proposed anti-inflammatory effects of fish oil may be linked to a change in cell membrane
composition. This altered membrane composition following fish oil supplementation [continues ...].
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Publication date
2013
Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.