The overarching aim of this thesis was to examine factors that affect post-exercise glycaemia and contribute to minimising the risk of hypoglycaemia after exercise. An inability to regulate circulating insulin concentrations is considered the primary gluco-regulatory defect within T1DM. Therefore, the aim of chapter 3 was to examine the effects of pre-exercise rapid-acting insulin reductions on blood glucose responses before and after running in T1DM individuals, to test the hypothesis that reducing pre-exercise insulin dose may help preserve post-exercise glycaemia. The results demonstrate that a 75% reduction to pre-exercise rapidacing insulin dose best preserved blood glucose before and after exercise, without increasing the risk of ketoacidosis, and reduced the risk of hypoglycaemia in free living conditions for 24 hours following running. An important factor determining blood glucose concentrations and subsequent patterns of fuel oxidation is the rate of appearance of carbohydrate into the circulation. Potentially, low GI carbohydrates may raise blood glucose less and increase the percentage contribution of lipids as a fuel because of a slower digestion. Therefore, the aim of chapter 4 was to examine the metabolic and blood glucose responses to ingestion of a high or low GI carbohydrate, combined with a 75% reduced insulin dose, before, during and for 24 hours after running. The results demonstrate that compared to a high GI carbohydrate, the low GI carbohydrate increased blood glucose concentrations less before exercise and maintained blood glucose better for 24 hours after running, via lower carbohydrate and higher lipid oxidation rates during the latter stages of running. After manipulating both the insulin dose and the pre-exercise carbohydrate GI, to improve post-exercise blood glucose concentrations, the timing of the ingestion of carbohydrate (alongside a reduced insulin dose) before exercise is an important factor which may further refine these strategies. Therefore, chapter 5 examined the metabolic and blood glucose responses to alterations in the timing of carbohydrate feeding and insulin administration prior to running. Our results demonstrated that administration of both a reduced rapid-acting insulin dose and low GI carbohydrate 30 minutes before exercise improved glycaemia for 24 hours after running, by reductions in carbohydrate oxidation, leading to increased carbohydrate availability post-exercise.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:678334 |
| Date | January 2011 |
| Creators | West, Daniel J. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://cronfa.swan.ac.uk/Record/cronfa43143 |
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