Approximately 1.2 million, or 5-6% of Australian adults have type 2 diabetes. Type 2 diabetes is often referred to as late onset diabetes, and is a systemic metabolic disease that causes reductions in insulin secretion and effectiveness. Regular exercise has been proven to be effective at promoting insulin secretion, improving insulin resistance and also reducing the risk of other conditions such as heart disease. But how does exercise actually help?
One of the ways in which exercise helps is via it’s effect on an important glucose (sugar) transporter protein called GLUT4. In type 2 diabetes there is a decrease in the function of this important transporter protein within muscle which means that less glucose moves from our bloodstream into our muscles. In recent years, researchers have shown that regular exercise can influence GLUT4 directly which results in an improved ability of our muscles to take up and use glucose.
Glucose is moved into the muscle via 2 main pathways. One of these pathways is dependant on insulin and the other is not. Exercise causes the activity of the pathway that doesn’t rely on insulin to increase, meaning that even if the insulin produced is lower or not as effective, there is still movement of glucose out of the bloodstream and into the muscles.
Another way in which exercise can help is specific to strength or resistance exercise. Increases in muscle strength and size result in an increase in the number of insulin receptors within the muscle itself, making it easier for glucose to find a passage into the muscle.
As mentioned earlier, type 2 diabetes is referred to as a systemic metabolic disease. There is often an increase in the inflammatory markers. Widespread inflammation can lead to a cascade of events that causes insulin to be dysfunctional. Exercise has been theorised to reduce and inhibit elements of the inflammatory process. Exercise also promotes the release of anti-inflammatory substances such as interleukin-6 which helps to control and reduce inflammation levels.
So what type of exercise is best?
There have been many research studies that have tried to find out whether aerobic exercise, resistance (strengthening) exercise or a combination of both is most effective. There is conclusive evidence that the combination of both aerobic and resistance exercise have the best impact on the management of type 2 diabetes. This is most likely due to the fact that managing diabetes involves an approach that tries to improve insulin function, control blood sugar levels and manage other risk factors such as obesity and inactivity. A well planned combination exercise program is most effective at targeting these different areas for greater overall impact.