The aims of the work described in this thesis are to examine the impact of physical activity/exercise and energy balance on metabolic control and inflammation and specifically whether exercise has independent benefits on various health-related outcomes above a role in energy balance.Chapter 3 examined whether a lifestyle intervention combining dietary advice with increased physical activity would further improve inflammatory markers compared to dietary advice alone and usual care in 494 patients with newly diagnosed type 2 diabetes. Motivational unsupervised diet and diet plus physical activity interventions led to reductions in inflammatory markers. Interestingly, there was no greater benefit from adding physical activity advice to dietary advice. Chapter 4 investigated whether daily vigorous-intensity exercise would counteract the metabolic changes induced by short-term overfeeding and reduced physical activity independent of any net attenuation of energy imbalance in healthy young men. The overfeeding and reduced activity model induced a state of insulin resistance, hyperinsulinaemia and altered expression of several key genes within adipose tissue. The inclusion of a daily vigorous-intensity exercise bout largely prevented these changes from taking place independent of any net effect on energy imbalance. Chapter 5 examined whether caloric restriction combined with vigorous-intensity exercise would further improve metabolic control and inflammatory markers compared to moderate-intensity exercise in middle-aged, overweight/obese men and postmenopausal women. Three weeks of caloric restriction combined with either vigorous or moderate-intensity physical exercise improved insulin sensitivity, lipid profiles and markers of inflammation. These results confirm the positive effects of combined caloric restriction and increased exercise in sedentary overweight men and women, but that exercise intensity does not seem to be so important. In conclusion, this thesis presents reasonable evidence that exercise per se has a positive impact upon metabolic control and inflammation independent of energy balance during an energy surplus but that a role in contributing to the health benefits during an energy deficit are less convincing.
|Date of Award||11 Dec 2013|
|Supervisor||Dylan Thompson (Supervisor) & James Betts (Supervisor)|