The Effect of Functional Exercises Training on Glycemic Control and Nerve Conduction Velocity in Patients with Type 2 Diabetes

Diabetes is a chronic metabolic disease that is spreading rapidly around the world (1). Diabetic neuropathy is a common complication of diabetes, with progressive destruction of the sensory and motor nerves of the lower extremities in these patients. Peripheral nerve problems in these patients also lead to functional deficits and muscle mobility (5, 6). In general, it is agreed that metabolic and vascular disorders caused by diabetes lead to peripheral neuropathy and nerve damage in these patients (8). Based on the hypotheses that cause diabetic neuropathy, it can be said that the use of exercise can be effective in improving diabetic neuropathy by improving vascular function (13, 14) and controlling blood sugar (13-15). The present study was to determine the effect of a period of functional training on blood sugar control and nerve conduction velocity in patients with diabetic neuropathic disorders. Diabetic neuropathy is a common complication of diabetes, with progressive destruction of the sensory and motor nerves of the lower extremities in these patients. Peripheral nerve problems in these patients also lead to functional deficits and muscle mobility (5, 6). In general, it is agreed that metabolic and vascular disorders caused by diabetes lead to peripheral neuropathy and nerve damage in these patients (8). Based on the hypotheses that cause diabetic neuropathy, it can be said that the use of exercise can be effective on diabetic neuropathy by improving vascular function (13, 14) and controlling blood sugar (13-15). The present study was to determine the effect of a period of functional training on blood sugar control and nerve conduction velocity in patients with type 2 diabetes.

In the present quasi-experimental study, 12 patients with type 2 diabetes living in Karaj (45-65 years old) were selected as the research sample and randomly divided into 2 groups of 6 exercise and control intervention. The training protocol in the present study was a researcher-made protocol that adjusted the volume and intensity of training based on exercise recommendations for patients with type 2 diabetes. The training program was performed for 8 weeks and 3 sessions per week. These exercises were designed as exercises at home. The exercises were designed to improve general endurance, endurance, strength, muscle flexibility and balance and with the approach of improving the function of the neuromuscular system and were designed as a station (20). In order to study blood variables 48 hours before and 48 hours after the intervention, fasting blood sampling was performed and electromyography devices were used to evaluate the nerve conduction velocity (21). Dependent t-test and independent t-test were used for statistical analysis; Statistical analysis was measured using SPSS software version 26 and the significance level was P <0.05.

According to the results of paired sample t-test  after the training period, a significant decrease where founded in fasting blood sugar (P = 0.046), fasting insulin (P = 0.033) and insulin resistance (P = 0.028) and a significant increase There was founded in median sensory nerve conduction velocity (P = 0.037) and a median motor nerve conduction velocity (P = 0.001) in the exercise group compared to baseline values, but no significant difference was observed in the measured variables in the control group ( P < 0.05). In comparison between the changes, the results of independent t-test showed that there were significant differences in fasting blood sugar (P = 0.007), fasting insulin (P = 0.019), insulin resistance (P = 0.005), Median sensory nerve conduction velocity (P = 0.005) and median motor nerve conduction velocity (P <0.001) compared to the control group.

The results of the present study showed that after the training period, a significant decrease in levels of fasting blood sugar, fasting insulin and insulin resistance was observed compared to the control group without exercise. Due to the pathology of type 2 diabetes and insulin resistance in insulin-sensitive tissues such as muscle tissue and adipose tissue, blood glucose levels increase in these people, and due to increased hyperglycemia, diabetic patients develop complications of diabetes, including neuropathy (7). Even a session of physical activity has been reported to stimulate glucose uptake by upregulating GLUT4 levels in sarcoma. This effect is independent of the effect of insulin and glucose uptake continues for several hours after the end of physical activity. Physical activity also increases insulin sensitivity in skeletal muscle; this effect lasts for several hours after the end of physical activity and is clearly dependent on insulin and insulin function in target tissues (22). Regarding the chronic effect of regular exercise on blood sugar control in patients with diabetes, it can be said that regular exercise helps control blood sugar and thus reduces hyperglycemia in these people due to increased cell sensitivity to insulin-dependent molecular pathways. Which improve insulin signaling (ACC and MAPKs PI3-kinase) as well as insulin-independent pathways (Akt and mTOR AMP-kinase), control glycemia in patients with type 2 diabetes and prevent the complications of diabetes (1, 13, 23). In investigating the effect of exercise on nerve conduction velocity, the results of our study showed that after the training period, a significant increase in sensory and motor nerve conduction velocity was observed compared to the pretest and control group; The results of our study showed the effect of almost twice the effect of exercise on increasing the conduction velocity of the median motor nerve compared to the conduction velocity of the median sensory nerve. The conduction of a shock in the human nerve depends on the electrochemical activity of single nerve fibers within the nerve (26). In their study, Galliro et al. (2021) reported that the rate of nerve conduction decreases in diabetic neuropathy, especially in the sensory fields in the lower extremities (18). It has been shown that metabolic abnormalities seen in impaired glucose tolerance may lead to changes in neural conduction (27). Given that diabetic neuropathy is associated with poor glycemic control, and in our study, increased nerve rate was negatively associated with insulin resistance, an increase in nerve conduction velocity can be justified; Research on laboratory animals has shown that exercise improves nerve function through adaptations in the presynaptic and postsynaptic sections (29). It has also been reported that impaired neural conduction in diabetic patients with mild to moderate peripheral neuropathy may be improved by drug doses of antioxidant supplements such as vitamin E (30). Although in the present study, factors related to free radicals, inflammatory factors or total antioxidant levels were not measured and were one of the limitations of the present study, but according to previous research results that show antioxidant and anti-inflammatory effects of exercise in diabetes (31), it can be said that exercise, like antioxidant vitamins, can improve nerve function. Overall, the results of the present study showed the positive effects of functional exercises on metabolic indicators and also increased nerve conduction velocity, which indicates the positive effects of functional exercises on preventing the complications of diabetic neuropathy.