Type 2 diabetes has reached pandemic proportions worldwide, which is worrying because it is associated with an increased risk of cardiovascular disease and premature death, and also has significant economic consequences for sufferers.
An elevated blood sugar level is the hallmark clinical manifestation of this disease, primarily caused by a sedentary lifestyle, an impoverished diet and being overweight.
While physical inactivity is a key factor in the development of this disease, more and more studies are demonstrating that sufficient exercise can help people with prediabetes ward off the development of type 2 diabetes, and may even lead to normal blood glucose levels.
Prediabetes or impaired glucose tolerance
Prediabetes is the condition in which blood glucose levels are higher than they should be, but are not high enough for a diagnosis of diabetes type 2. Prediabetes is also called “impaired glucose tolerance” and is characterised by insulin resistance, which is when muscle, liver and fat cells do not respond properly to the blood glucose-lowering hormone insulin. Instead of waiting for full-blown type 2 diabetes to develop, with its need for therapeutic care and the associated negative consequences on health, we should encourage those with prediabetes to choose a lifestyle with more exercise and a proper diet in order to prevent the disease.
Physical activity reduces type 2 diabetes risk
Many studies have proven that regular, moderate to vigorous exercise can help prevent type 2 diabetes, especially when combined with a proper diet. The more people with prediabetes exercise, be it walking, running, cycling, swimming or working out at gym, the better their chances are of warding off type 2 diabetes. This exercise and healthy diet helps the impaired glucose tolerance to evolve into better blood glucose levels or, in some instances, back to a normal glucose tolerance. Often there is also a decrease in body weight, blood pressure and the level of blood lipids, which means that cardiovascular risk is also lowered. While some studies indicate that an intensive lifestyle intervention with more exercise and good eating habits can reduce the risk of diabetes by 58%, a meta-analysis of 20 studies showed that, in general, increased physical activity is associated with a 20 to 30 % reduction in diabetes type 2 risk. This risk reduction appears to be greatest in those with an increased risk of the disease, like the obese, those with impaired glucose regulation and those with a positive family history.
How much and what kind of exercise?
It is obvious that there is no “one size fits all” mass-population strategy when it comes to exercise, but tailored guidelines will provide the best success rates. In the above-mentioned study, data from six large-scale diabetes prevention studies in people with impaired glucose tolerance suggests that moderate physical activity of 150 minutes per week significantly reduces the risk diabetes progression, with this effect being greater if accompanied by weight loss. However, even at this level of exercise 2-13% per year still developed type 2 diabetes. Thus, while 150 minutes per week of moderate exercise shows benefits, higher levels of activity may be needed to maximise diabetes risk reduction in those at a high baseline risk for the disease.
Main supporting mechanisms
An increase in abdominal fat accumulation and a loss of muscle mass are heavily associated with the development of insulin resistance and impaired glucose tolerance in prediabetes. Since increased physical activity results in a loss of fat from the central regions, it contributes significantly to alleviating insulin resistance. Likewise, weight training can prevent muscle loss and stimulates further muscle development, which also decreases insulin resistance.
Exercising with type 2 diabetes
While there is enough evidence that more physical activity can reduce the risk of developing type 2 diabetes, evidence that exercise and training is beneficial in the treatment of type 2 diabetes itself was not that strong. A recent study that examined the results from meta-analyses of studies on the effects of supervised exercise in patients with type 2 diabetes, clearly demonstrated that physical activity has benefits on blood glucose levels (with an average reduction of glycated haemoglobin of 0,6 %) and cardiovascular risk factors. Of course, the main mechanism involved was the lowering of insulin resistance, a phenomenon that was not only seen in the muscles, but also in liver and fat tissue.
Dr Geert Verhelst is a Belgium-based GP and medical homeopath with a particular focus on the holistic prevention and treatment of diabetes. He recently visited SA on a seminar tour for OTC Pharma SA, which produces the Diabecinn range of products for Type 2 Diabetes. See www.otcpharma.co.za.