Ageing refers to a multidimensional process of physical, psychological, and social change of an organism over time. As life expectancy increases the prevalence of ageing related diseases raises. Thus, it becomes essential to distinguish the contributions to health and disease of ageing per se and lifestyle. It is well established that increased physical activity can protect against metabolic diseases and reduce mortality. However, methods of inducing a durable increase in daily physical activity are not well established and there are particular difficulties in bringing about long term changes in behaviour. The interaction of physical activity with ageing is complex. It remains to be shown how much physical activity can modify age related sarcopenia. The work described in this thesis aimed to answer basic questions about motivation to exercise, effects of exercise and the interaction of physical activity and maintenance of muscle mass. The first study was conducted in order to determine the effect of physical activity and ageing upon body composition and mediators of glucose control. Liver lipid, skeletal muscle mitochondrial function, body composition, and metabolism were studied in different ages and physical activity levels. The main research questions were: 1. Does maintaining a physically active vs. sedentary lifestyle produce a different ageing phenotype? 2. Can these differences be characterised using non-invasive biomarkers? This cross sectional study raised awareness on the body composition changes with age which are affected by physical activity level. Additionally, metabolic consequences of ageing were examined and distinguished from those of deconditioning. Magnetic resonance analysis showed a decrease in mitochondrial function with ageing and an increase in liver fat, which was accompanied by insulin resistance. The second study evaluated whether goal orientated exercise advice held benefits for adherence, physical fitness and metabolic flexibility over non-Goal orientated advice in sedentary people. The data demonstrated the critically important factor of sustainability in an exercise program. Maintenance of the exercise regime was enhanced by a goal orientated exercise programme. Exercise alone did not produce a reduction in mean body mass even though compliance was good and physical fitness improved. This holds implications for patients and clinicians. Goal Orientated exercise focussed on mass participation exercise also produced greater metabolic adaptations than standard exercise advice alone. A sub analysis of the data aimed to assess whether increased physical activity had a beneficial effect on all people irrespectively of their ability to lose weight during an exercise intervention. Participants were divided into two groups according to their ability to lose body fat with exercise (Responders group and non-Responders group). The data showed that increased physical activity regardless of weight or fat loss can increase aerobic fitness at all ages with potential beneficial effect on quality of life, disease risk and reduction in mortality. Overall, this thesis describes new information on bringing about change in physical activity and the relationships between age, physical activity and sarcopenia.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:556012 |
| Date | January 2011 |
| Creators | Papakonstantinou, Lida |
| Publisher | University of Newcastle Upon Tyne |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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