F55. Moderate intensity exercise improves heart rate variability in obese adults with type 2 diabetes

Abstract

Introduction Obesity, a key risk factor for the development of type 2 diabetes, is associated with dysregulation of autonomic nervous function. Exercise therapy has been shown to improve autonomic nervous system modulation of heart rate variability (HRV) in healthy individuals. Therefore, exercise training may improve cardiac autonomic regulation in a variety of clinical populations including obese adults with type 2 diabetes. Thus, the main aim of this study was to determine the effect of thrice-a-week, six months, moderate aerobic exercise on cardiac autonomic function as measured by HRV in obese adults with type 2 diabetes. Methods 41 obese adults with type 2 diabetes participated in this study. Anthropometric and metabolic parameters were measured, and resting electrocardiogram (ECG) for the HRV analysis at spontaneous respiration was recorded for 5 min in supine position before and after six months of supervised aerobic training given thrice-a-week. Results The mean age, body mass index (BMI), and duration of diabetes of the study population were 44.1 ± 4.5 years, 30.94 ± 1.36 kg/m2, and 16.3 ± 2.7 years, respectively. In time domain variables, standard deviation of all RR intervals (SDNN), the square root of the mean of the sum of the squares of differences between adjacent RR intervals (RMSSD) and percentage of consecutive RR intervals that differ by more than 50 ms (pNN50) were significantly increased after exercise. In frequency domain variables, high frequency (HF) (ms2) and HF (nu) were significantly increased while low frequency (LF) (ms2) and LF/HF ratio were significantly decreased after exercise. But LF (nu) was unaffected after exercise. Conclusion Thrice-a-week, six-month, moderate, supervised aerobic training program in obese adults with type 2 diabetes who were clinically free of cardiovascular disease leads to significant improvements in cardiovascular autonomic function measured by HRV via increasing cardio-vagal tone and decreasing cardio-sympathetic tone.