The validity and reliability of ratings of perceived exertion (RPE) in isometric exercise training for the reductions of arterial blood pressure

Hypertension (HTN), characterised by a sustained elevation in arterial blood pressure (≥140 mmHg systolic and/or ≥90 mmHg diastolic), is the leading global risk factor for disease, ahead of tobacco smoking, household air pollution, dietary factors, and physical inactivity. In addition, HTN is the primary modifiable risk factor for the development of cardiovascular disease (CVD), the largest preventable cause of morbidity and mortality worldwide. Reductions of ≥5 mmHg in systolic and/or diastolic blood pressure (BP) result in a significant reduction in the risk of CVD, myocardial infarction, stroke, and mortality. Pharmacological treatment requires lifelong adherence to daily medication to successfully control BP to within clinical target ranges, which comes at a considerable economic, personal, and social cost, including undesirable side effects. As a result of this, the adherence to and effectiveness of medical interventions for high BP is low. Exercise has been recommended as a non-pharmacological lifestyle modification for the treatment of HTN, with isometric exercise (IE), including isometric wall squat (IWS) exercise, proving to be an effective and time efficient means of reducing resting and ambulatory BP. However, the previous methods used to prescribe and implement IE interventions have mostly required expensive and/or specialised equipment, laboratory visits, and maximal exercise testing, which may reduce uptake and adherence to these programmes. The use of ratings of perceived exertion (RPE) to prescribe and control IE training intensity could potentially overcome a number of these barriers. Therefore, the aims of this thesis were to (1). validate RPE for use during IWS exercise, and (2). implement a home-based exercise intervention using RPE as a more accessible means of prescribing and controlling IWS exercise intensity. The initial studies in this thesis demonstrated the validity and reliability of RPE during the IWS protocols currently used in interventions for BP reduction. Then, a 4-week home-based IWS intervention was implemented, in a mixed group of normotensive and pre-hypertensive males and females, using a novel RPE method to prescribe and monitor exercise intensity. Following the intervention, 100% of the participants successfully achieved a clinically important reduction in BP. This included significant reductions in resting systolic, diastolic, and mean arterial BP, and ambulatory systolic BP, when compared to a control group. This novel prescription method may make IE more accessible by removing proven barriers to participation. This may in turn increase the uptake, adherence to, and overall effectiveness of IWS interventions for the reduction of resting BP.