Diabetes Susceptibility with Age: A Statistical Study Using Heart Rate Variability (HRV)

Abstract

Background: Heart rate variability (HRV) reflects autonomic modulation of cardiac activity and may vary with age and diabetes mellitus. This study examined age- and diabetes-associated patterns in HRV using short-term electrocardiogram (ECG) recordings. Methods: Six-minute lead-II ECG signals were acquired at 256 Hz using a custom-made three-lead ECG system from 20 young healthy controls, 20 older healthy controls, and 18 diabetic patients. The signals were preprocessed, RR intervals were detected using a MATLAB-based algorithm, and HRV was analysed in Kubios using time-domain, frequency-domain, and nonlinear measures. Results: Compared with young healthy controls, the older and diabetic groups showed lower mean values for SDNN, RMSSD, NN50, pNN50, TINN, total power, SD1, and SD2. Mean total power was 5854.80 ms² in young healthy controls, 1620.80 ms² in older healthy controls, and 1593.94 ms² in diabetic patients. Mean SD1 values were 52.92, 12.56, and 11.13 ms, respectively, while mean SD2 values were 98.66, 47.94, and 51.41 ms. The diabetic and older healthy groups displayed broadly similar descriptive HRV patterns. Conclusion: The findings indicate lower cardiac autonomic variability in the older and diabetic groups under the study conditions. Larger, matched studies with standardised recording conditions and inferential analyses are required.