Effectiveness of Exercise Training on Asymptomatic Cardiac Autonomic Neuropathy in Type 2 Diabetes

Abstract

The objective of this study was to evaluate the effectiveness of exercise training on asymptomatic or subclinical cardiac autonomic neuropathy in type 2 diabetes. Ninety-one patients who had been classified as mild cardiac autonomic neuropathy(standard cardiac autonomic function test score 1-2.5) were recruited. All subjects were randomly allocated into control (n=47) and exercise (n=44) groups. Subjects underwent standard cardiac autonomic function tests, measurement of peak oxygen uptake (VO[subscript 2]peak), and determination of plasma glycosylated hemoglobin(HbA1c) level before and after intervention. Exercise training was performed by bicycle ergometer or treadmill for the period of twelve weeks. Exercise intensities were set at 50%-60% of individually maximum work load at VO[subscript 2]peak with duration of 30-60 minutes and frequency of 3 sessions per week. The improvement of cardiac autonomic function was defined as a decrease in autonomic cardiac function test score of [is more than or equal to] 1. After 12 weeks of exercise training, there was significant improvement in autonomic function score of the subjects in exercise group (22.72%,n=10/44), compared with the control group(6.38%,n=3/44),[%diff.(95%CI)=16.34%(2.13 to 30.56),P=.04]. The VO[subscript 2]peak was significantly increased from baseline by 1.79 +- 1.51(ml/kg/min) in the exercise group, and increased by 0.71+-1.95(ml/kg/min) in the control group [mean diff.(95%CI)=1.08(0.35 to 1.82), p<.01], and the HbA1c level was significantly decreased from baseline on average by -0.51+-0.74 % in the exercise group, and increased by 0.060.46 % in the control group [mean diff. (95%CI)= -0.57(-0.83 to -0.32), P<.01], respectively. The result of this study indicated that moderate aerobic exercise training can improve cardiac autonomic function in asymptomatic cardiac autonomic neuropathy type 2 diabetes.