Resistance training to prevent and improve type 2 diabetes: resist diabetes

Type 2 diabetes is a condition of chronic hyperglycaemia and insulin resistance. Currently it is estimated that 1-2 million Australians have type 2 diabetes with this predicted to increase by 47% over the next 20 years. Treatment of type 2 diabetes is complicated through diabetes related conditions of retinopathy, neuropathy and cardiovascular disease. Lifestyle modifications such as exercise have been recommended as the first line of treatment, followed by oral hypoglycaemic medications and exogenous insulin injections to control blood glucose levels. With this in mind, expert authorities have made recommendations about the type and volume of exercise that people with type 2 diabetes should complete.

This PhD thesis set out to explore the acute and chronic effects of resistance exercise, prescribed in accordance with guidelines produced by expert authorities. An initial observation is that resistance exercise guidelines vary between authorities and appear to have little supporting scientific evidence derived from populations with type 2 diabetes. The aims of the series of closely linked studies presented in this thesis were to determine the effects of resistance exercise on insulin sensitivity and glucose control, and to generate data that may inform a more precise resistance exercise prescription for this population.

The series of studies completed for this thesis suggest that a single session of resistance exercise, following the broad exercise guidelines currently available for people with type 2 diabetes, has either no impact, or a short-term impairment on insulin sensitivity and glucose control in both apparently healthy individuals and those with type 2 diabetes. Interestingly this appears to be in contrast to data reported following exercise completed at a low intensity following a single exercise session or high intensity after a period of chronic exercise training. Without being able to accurately define the frequency of resistance training required to first improve and then maintain insulin sensitivity and glucose control, this dissertation has provided valuable information from which further studies can be designed to identify the minimum effective exercise prescription in people with type 2 diabetes. What can be concluded though is that for resistance exercise to be effective, it needs to be completed on a regular basis. The studies in this thesis have investigated resistance exercise prescribed in accordance with the current broad exercise guidelines and shown minimal effect on insulin sensitivity and other markers of metabolic health. Therefore, further research should be conducted using intensities different to those currently recommended, such as low intensity resistance training, to elucidate optimal gylcaemic control for both novice and trained people with type 2 diabetes.