Physical activity and cognition in the elderly
2013-06-13T10:19:24Z (GMT) by
Dementia is a common cause of disability in the elderly and, in the absence of a successful long-term treatment, it is important to investigate possible lifestyle interventions to help reduce an individual s risk of developing the condition. This thesis investigated the relationship between physical activity and dementia risk, finding that not all research supports the link. The literature review presented in this thesis (Chapter 2) highlighted several possible mediating factors, specifically the type of physical activity performed, the cognitive domains being studied and participant characteristics. Women seemed most susceptible to the effect of physical activity and some other forms of midlife interventions, possible mechanisms for which were discussed in another review (Appendix A). The cognitive test battery to be used in later studies was evaluated for its relevance to dementia and treatment during a 6-month study of Alzheimer's disease patients and their carers (Chapter 3). Memory tasks were found to be especially sensitive to clinical outcomes of dementia treatment (Chapter 4). An observational study of Indonesian elderly found a positive relationship between physical activity and memory performance on the same tests. This effect was strongest in women and in those with no pre-existing cognitive impairment (Chapter 5). However, the relationship could be further modified by other demographic factors, such as education. Health was independently affected in this model by exercise and its association with engaging in physical activity in this cohort was further investigated in Chapter 6. A randomised controlled trial (Chapter 7) was conducted to assess the effect of a 12-week programme of non-aerobic physical activity in sedentary middle-aged adults. Results indicated that resistance training, but not flexibility exercises, influenced memory but not executive function. Overall, this thesis suggests that several types of physical activity may be effective at slowing cognitive decline in elderly groups who are at increased risk of dementia, such as those in middle age and elderly women (Chapter 8). These findings should be expanded with the aim to improve healthcare advice and influence policy-making.