A large number of studies have shown that habitual physical activity reduces the risk of coronary heart disease, stroke, colon cancer and mortality from all causes. Physical activity also positively affects the metabolism of glucose in both healthy people and those suffering diabetes mellitus. In type 2 diabetes mellitus, regular aerobic physical activity is an effective tool for both prevention and treatment and needs to be fully implemented. Intervention trials have demonstrated that in subjects with impaired glucose tolerance diet plus exercise programmes reduce the risk of developing diabetes by over 60%. In subjects with overt type 2 diabetes, diet and exercise produce greater weight loss and allow greater reductions of hypoglycemic medications than diet alone.
Nevertheless, despite the evidence about the benefits of exercise, many diabetologists do not spend time and efforts convincing type 2 diabetic subjects to practice physical activity regularly. This may be due to the poor adherence of older adults to comply with their recommendations. Survey studies have shown that adults with diabetes are less likely than adults in general to engage in regular physical activity and that only 23% of older adults with type2 diabetes reported more than 60 minutes of weekly physical activity. In type II diabetic patients that do exercise regularly, reductions of BMI, HbA1c (glycated haemoglobin), coronary risk and treatment costs occurred. Data of literature showing that modest increments of physical fitness in diabetic subjects reduce by two-fold the risk of overall mortality, urge the implementation of physical activity programmes in the cure of type 2 diabetes mellitus.
Long-term effects of regular exercise are particularly advantageous for type 2 diabetic patients. Regular aerobic exercise reduces visceral fat mass and body weight without decreasing lean body mass, ameliorates insulin sensitivity, glucose and blood pressure control, lipid profile and reduces the cardiovascular risk. For these reasons, regular aerobic physical activity should be considered an essential component of the cure of type 2 diabetes mellitus.
Both aerobic and resistance training are recommended to control blood glucose in people with diabetes. However, only a few studies have attempted to compare the benefits from the two forms of exercise. A study by Zisser et al published in 2011 directly compared the effects of 10 weeks of resistance training or treadmill workouts on blood sugar levels before and after exercise and also HbA1c.
Both intervention groups met three times per week for 10 weeks under supervision of an exercise therapist. In both groups, exercise intensity progressively increased over the course of the study. Special care was taken to ensure that total energy expenditure, perceived exertion and heart rate were equivalent between treatments.
Pre- and post-exercise blood glucose levels as well as HbA1c values were improved in both groups. However, the resistance training group clearly had greater benefit in achieving glycaemic control. After the 10-week resistance programme, 80% of the subjects had post-exercise blood glucose levels within the normal range, while only 20% of the aerobic group reached this goal. Additionally the resistance training group had significantly greater reductions in HbA1c compared with the aerobic group. Although aerobic training did result in statistically significant reduction in HbA1c, none of the subjects in the aerobic group reached the target HbA1c < 7.0% while 40% of the resistance exercise group achieved this goal. Indeed, resistance training reduced the value of HbA1c by an average of 18% compared with an 8% reduction in the aerobic group.
Ten weeks of resistance training resulted in significantly better improvements in glycaemic control compared to isocaloric and equally difficult aerobic exercise.