[Truncated abstract] Exercise is generally recommended for individuals with type 1 diabetes mellitus since it is associated with numerous physiological and psychological benefits. However, participation in exercise can also increase the risk of experiencing severe hypoglycaemia both during exercise and recovery. Unfortunately, existing guidelines to minimise the risk of exercise-induced hypoglycaemia are often general and fail to take into account that different precautions are required for exercise of varying type, duration and intensity. Specifically, there are no evidence-based guidelines for safe participation in intermittent high-intensity exercise (IHE), which characterises the activity patterns of most team and field sports, manual labour occupations and spontaneous play in children. This is because the response of blood glucose levels to this type of exercise is not known. Consequently, the purpose of this thesis was to investigate the glucoregulatory responses to IHE that replicates the high-intensity work-to-recovery ratios observed in intermittent sports in individuals with type 1 diabetes, in order to assess the associated risk of hypoglycaemia. The first study of this thesis examined the effect of the repeated bouts of high-intensity exercise that characterise IHE compared to remaining inactive, on blood glucose and glucoregulatory hormone levels in individuals with type 1 diabetes. Eight healthy individuals with type 1 diabetes were tested on two separate occasions during which either a 20 minute rest (CON) or an IHE protocol designed to simulate the activity patterns of team sports was performed (repeated 4 second sprints every 2 minutes). ... During the second hour of recovery, Ra and Rd returned to baseline following MOD, but remained elevated after IHE. These changes in Ra and Rd were consistent with a lower glucose infusion rate (GIR) during early recovery from IHE and a higher GIR after 2 hours of recovery compared to MOD. In conclusion, the repeated bouts of high-intensity exercise associated with IHE stimulate a more rapid and greater increment in Ra during exercise and attenuate glucose Rd during early recovery. These findings assist in explaining, in part, the previous observation that the risk of hypoglycaemia might be lower during IHE and early recovery compared to MOD. Overall, the findings of this thesis have implications for current recommendations aimed at managing blood glucose levels during and after exercise to avoid hypoglycaemia.

Thesis (M.S.)--Indiana University, 2006. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (M.S.)--Indiana University, 2006. / Includes bibliographical references.

Thesis (M. Heal. Sc.)--University of Canterbury, 2007. / Typescript (photocopy). Includes bibliographical references (p. 341-361). Also available via the World Wide Web.

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Bibliographical references: leaf 243-269.

Type 2 diabetes mellitus (T2DM) is mainly caused by genetic modifications and inappropriate life styles. The complexity of T2DM has brought us challenges for a comprehensive understanding of altered metabolic pathways that contributing to the development of T2DM. Therefore, a comprehensive metabolic analysis is needed. To date, taking regular exercise is a common and effective therapeutic way known to antagonize the metabolic disorders of T2DM. However, the regulatory effects of exercise on T2DM or T2DM induced complications have not been clearly characterized. Here, we present the effect of physical activity on biochemical changes in diabetic db/db mice in plasma, urine, skeletal muscle and kidney samples. Based on liquid chromatography coupled with high resolution Orbitrap mass spectrometry (LC-MS) and gas chromatography coupled with mass spectrometry (GC-MS), two major approaches, untargeted and targeted metabolomics studies, have been developed to delineate metabolic signatures in various kinds of biofluid and tissue samples. Targeted quantification methods on acylcarnitines and acyl-CoA have been developed. Untargeted metabolomics analysis by GC-MS and LC-MS have also been developed to draw a more comprehensive view of the metabolic changes in response to T2DM and exercise on db/db diabetic mice. The transcript expressions of mRNA in pathways of interest have also been measured to confirm the hypothesis. Firstly, a targeted quantification method of acylcarnitines by using high resolution parallel reaction monitoring (PRM) on LC-MS platform has been developed. A total of 117 acylcarnitines were detected from plasma and urine samples. The application of targeted profiling of acylcarnitines in db/m+ control and db/db diabetic mice indicated incomplete amino acid and fatty acid oxidation in diabetic mice. Interestingly, the reduction of medium odd-numbered chain acylcarnitines in urine samples was firstly observed between db/m+ and db/db mice. The high resolution PRM method makes it possible to monitor the widespread metabolic changes of the acylcarnitines in response to stimuli. Besides, the accurate MS and MS/MS spectra data of the 117 acylcarnitines could be used as mass spectrometric resources for the identification of acylcarnitines. In addition to targeted metabolomics analysis, untargeted metabolomics profiling analysis in plasma samples indicated that db/db diabetic mice may be more susceptible to exercise for energy expenditure. Interestingly, all the results from plasma, skeletal muscle and kidney samples may demonstrate that physical activity could mitigate insulin resistance in T2DM mice through improving fatty acid β-oxidation (FAO) and eliminating overloaded intermediate which contribute to insulin resistance. Specifically, the results from kidney samples demonstrated that exercise exhibit beneficial effect in reducing hyperlipidemia, expression levels of inflammatory markers (TNFα, IL-6 and COX2) and fibrosis markers (Collagen 1), and alleviating diabetic nephropathy (DN) induced mesangial expansion in kidneys of diabetic mice. The results of metabolic changes in kidney of db/db mice revealed that the accumulation of acyl-CoA, phospholipids and hydroxylated acylcarnitines were substantially ameliorated by exercise, and the reduction of important enzymes CTP1α and Acadl in FAO were partially reversed. In addition, branched-chain amino acids (BCAA) metabolism which positively related to inflammation (TNFα) was down-regulated in DN mice by exercise. What’s more, the accumulation of uric acid, which contributes to inflammation and tubulointestitial fibrosis in kidney disease, together with its six precursors have also been substantially reduced. The results in kidney samples demonstrated that in addition to beneficial effect in alleviating lipotoxicity through improving FAO efficiency, exercise also ameliorated diabetic induced inflammation and fibrosis via promoting BCAA catabolism and accelerating the elimination of uric acid. Together, the mass spectrometry-based metabolomics study is a powerful tool to investigate the regulatory effect of exercise on complex metabolic diseases. The results may provide informative insights into the underlying the mechanism of exercise on T2DM and T2DM induced complications.

No description available.

Although the benefits of exercise to non-insulin-dependent diabetes mellitus (NIDDM) are well-known, individuals with NIDDM are at risk for macrovascular and microvascular complications associated with an abnormal systolic blood pressure (SBP) elevation during exercise. In order to compare the SBP and rating of perceived exertion (RPE) response between individuals with NIDDM and apparently healthy controls during submaximal exercise, eight individuals representative of each group completed a 10-minute submaximal treadmill exercise trial at 65% of functional capacity. Heart rate, blood pressure and RPE were monitored throughout the trial. Between group comparisons were made for SBP and RPE response, and the frequency of exercise SBP response _> 200 mmHg was investigated. No significant differences were observed in either SBP or RPE response between groups during the submaximal treadmill trials. In addition, none of the subjects from either group achieved a SBP ? 200 mmHg. While this study indicates that exercise at 65% of functional capacity is safe for this particular group of subjects with NIDDM, additional research is warranted to investigate cardiovascular response to exercise in a broader subject pool representative of the entire NIDDM population. / School of Physical Education

The purpose of this thesis was to aid in the development of a web-based physical activity intervention for people with type 2 diabetes living in remote and rural areas. Chapter 1 introduces the research area, the design of the thesis and the key research questions. The thesis is then made up of 5 key studies. Study one, a systematic review of the literature was conducted and reported in chapter 2. This review identified the technologies that have previously been used to promote physical activity in type 2 diabetes, it identified the methodological quality of each included technology and the key components for effective change. Web based technology was the most commonly used and the most effective in increasing physical activity using components such as goal setting and physical activity trackers. These results informed study 2 (chapter 3) which explored patient and health professional's views on diabetes, physical activity and use of the internet. The need for clear information was identified with regard to diabetes as well as the call for accurate physical activity advice in relation to diabetes for both patients and health professionals. Study 3 (chapter 4) explored key information and components for an effective website. Included features were the need for a personalised approach; detailed advice on how the body responds to physical activity; a physical activity tracker and goal setting. The need for a 'virtual trainer' for support, advice and help with goal setting and interactive maps showing physical activity opportunities were all deemed important. The fourth study, chapter 5 described the design of the website and its features as well as the protocol for a six month pilot randomised controlled trial to examine the effectiveness of the development website, with and without interactive design elements. The final study in this thesis (chapter 6), describes the physical activity, physiological and biochemical results from a randomised controlled trial to test the effectiveness of the website and its features. The final chapter summarises the findings in response to the research questions and the future recommendations based on the outcomes.

The aim of this study was to gain insight into the exercise practices, in conjunction with dietary habits and medication routine of insulin dependent diabetics. The study design adopted for the study was that of descriptive and analytical survey. The gathering of data was conducted over a period of seven months using a questionnaire as a data collection instrument, which was administered to 200 insulin dependent diabetics utilizing the outpatient facilities at 12 hospitals in Kwa-Zulu Natal. In determining the respondent's attitude towards exercise, the significant (p<0.001) overall majority (85%) had a positive attitude towards exercise. In probing the perceived efficacy of exercise as a therapeutic modality, a significant (p<0.001) majority (93%) of the respondents stated that exercise/sport is beneficial to a diabetic. Of the overall sample, the significant (p<0.001) majority (68%) of respondents were active participants in exercise (exercisers) versus 32% who were not active (non-exercisers). The profile of the exercisers indicated that the significant (p<0.001) majority participated in exercise of an aerobic type at frequency of 4 or more times per week, at an intensity eliciting an approximate heart rate of between 110 to 130 beats per minute corresponding with an RPE of 11 to 13, for a duration of 20 to 45 minutes. A significant (p<0.001) overall majority (98%) stated that a good diet is an important factor when trying to achieve near normoglycemia. In probing the respondent's knowledge as to what group certain types of food belong to, an overall significant (p<0.001) majority (82%) was accurate in this regard, while significantly (p<0.1) more exercisers (84%) were aware of correct food grouping than non-exercisers (67%). In probing their knowledge of the normal range of blood glucose levels, an overall significant (p<0.001) number of respondents (66%) stated a correct response, while exercisers (67%) were significantly (p<0.1) more knowledgeable than non-exercisers (52%) in this regard. The significant (p<0.001) majority of respondents injected themselves three and more times a day (54%), before meals (71%), in the thigh (35%) and abdominal areas (48%), as opposed to the gluteal area (10%) and the arm (8%). The mean overall dosage of long-acting insulin (12.2 units) and short-acting insulin (10.5 units) for lunch was significantly lower (p<0.1) than for breakfast and supper, however there was no significant difference (p>0.1) between the breakfast and supper dosages. The same pattern was observed for non-exercisers and exercisers. The respondent's knowledge of good diabetic management goals reflected that a significant (p<0.001) overall majority (83%) were aware that diet, insulin and exercise are all important constituents in obtaining good diabetic management, while significantly (p<0.1) more exercisers (84%) than non-exercisers (71%) were aware of this. A significant (p<0.001) majority (83%) of non-exercises stated that they were willing to participate in exercise, but cited time constraints and physical discomfort, inter-alia, as antecedents to non-participation. In conclusion, the results indicated that the provision of educational support for insulin dependent diabetics to overcome the perceived barriers to exercise would increase participation, enhance appropriate exercise prescription and compliance to this important aspect of the diabetic regimen. / Dissertation (MA (Human Movement Science))--University of Pretoria, 2002. / Biokinetics, Sport and Leisure Sciences / unrestricted