An examination of physical exercise as an adjunct treatment for depressive symptoms in adults aged 65 years and older

Abstract

In light of impending demographic shifts and projected strain on healthcare systems, this thesis set out to progress our putative understanding of the benefits of physical exercise on mental health in older adults aged 65 years and over. Herein, four studies of divergent research design interrogated the current knowledge base relating to the potential benefits of exercise in older adults with depressive symptomology. Study 1 set out to establish preliminary experimental evidence that four years of unsupervised aerobic exercise can improve cardiorespiratory function (determined by VO2max) and health-related quality of life (HRQL) in lifelong sedentary ageing men compared with lifelong exercising athletes. Results demonstrated preliminary proof of concept for exercise-induced benefits on cardiorespiratory function and HRQL in ageing men. Study 2 surveyed community-dwelling older adults (n = 586) to establish a hierarchy of exercise-associated factors to predict depressive symptomology. Contrary to expectation, exercise behaviour did not confer additional antidepressant effect, but was substantially predicted by exercise-induced mood, exercise self-efficacy, and social support (f2 = 0.993). Study 3 pooled evidence from randomised controlled trials (RCTs) to quantitatively compare the treatment effectiveness from aerobic, resistance and mind-body exercise training in older adults with pre-existing clinical depression, whereas Study 4 followed the same methodology in apparently health older adults without pre-existing clinical depression. Using network meta-analytical techniques, both clinical depressed (g = -0.41 to -1.38) and apparently healthy (g = -0.27 to -0.51) older adults demonstrated equivalent effectiveness for aerobic, resistance, and mind-body exercise interventions, with encouraging levels of study compliance. Taken together, these findings encourage personal exercise preference when prescribing either aerobic, resistance, or mind-body exercise as a treatment adjunct for clinical depression and older adults with symptoms thereof. The sum of works herein provide new knowledge to guide exercise prescription for stakeholders in mental health and older adults over 65 years.Doctor of Philosoph