Exploring Exercise Intensity in Outpatient Cardiac Rehabilitation and Home Environments.

Student thesis: Doctoral Thesis


Cardiovascular disease (CVD) is the leading cause of death globally and is a large contributor to the economic burden of disease. Cardiac rehabilitation (CR) is an important secondary prevention tool in the management of CVD. Research has shown CR improves cardiovascular mortality and morbidity.
Exercise is a key component of CR, however, there has been minimal research investigating specific exercise parameters being used within CR programmes in Australia. There is emerging evidence to suggest high intensity interval training (HIIT) may be superior to traditional recommendations of moderate intensity continuous training (MICT) in improving cardiorespiratory fitness (CRF).
However, there is minimal research investigating to what extent HIIT is being used within CR exercise programmes in Australia, nor has there been a compilation of reported adverse events occurring within the cardiac population when using HIIT.

Additionally, CRF must be maintained to provide cardio-protection long term, however there is limited research investigating the long term adherence to exercise or the amount, and intensity, of exercise currently performed by people with heart disease once they are discharged from the subacute phase (outpatient phase 2) of CR and enter the maintenance phase (Phase 3).
Although wearable physical activity monitoring devices (WPAM) have grown in popularity and thought to improve exercise adherence, there is minimal research surrounding the benefits of utilising these devices for people with cardiac disease. These devices generally measure step count which does not take into account the intensity of exercise. Intensity is important to stimulate physiological adaptation to improve CRF and other cardiometabolic health outcomes.

The aims, therefore, of this thesis were firstly, to evaluate and synthesise current literature comparing improvements in physiological benefits, particularly CRF (VO2peak) between participants diagnosed with CVD engaged in MICT versus HIIT, analyse the effect of VO2peak changes resulting from different durations of interventions and collate reported adverse events occurring within eligible randomised controlled trials (RCTs). Secondly, to collect data surrounding current exercise prescription parameters and clinician perceptions about implementation of HIIT, and current usage across Australia. Thirdly, to investigate the effect of WPAM within the cardiac population on CRF and finally, to evaluate the effect monitoring Personal Activity Intelligence (PAI) scores, using a WPAM, has on intensity, adherence and motivation in the maintenance phase of CR.

This thesis has resulted in numerous insights to improve CR delivery.
The results will hopefully aid in encouraging uptake of HIIT as an important tool in exercise prescription for people with cardiac disease. Particularly as the results further support the evidence to utilise HIIT as it is superior to current exercise prescription practices (MICT) in improving CRF and appears as safe as MICT.

Important considerations to improve Australian CR practices have been highlighted, particularly the lack of reassessment currently being performed within the exercise component by Australian CR programmes, thus quality of programmes cannot be adequately determined. CR is also not being offered frequently enough, nor long enough, to encourage lifetime exercise behaviour changes.

This thesis indicates that during the maintenance phase participants should utilise a WPAM as greater gains in CRF were shown. Monitoring a new exercise metric, PAI, is a promising adjunct and should be encouraged as viewing PAI significantly increased the amount of exercise performed by participants. In addition, all participants found the concept of PAI interesting and most participants stated it increased their motivation to exercise. These findings are original contributions to improve the knowledge in the area of exercise prescription and intensity in outpatient CR and home environments.
Date of Award3 Feb 2021
Original languageEnglish
SupervisorWayne Hing (Supervisor), Jeff Coombes (Supervisor), Michael Climstein (Supervisor), Rohan Jayasinghe (Supervisor) & James Furness (Supervisor)

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