Assessment of heart rate variability indices in overweight and obese Indian population

Abstract

Background and Aim: Due to the increased incidence of overweight and obesity, its associated co-morbidities have also been reported to be escalating. Resting tachycardia, increased rate pressure product (RPP) and decreased heart rate variability (HRV) contribute to cardiovascular (CV) risks. Therefore, in the present study HRV indices and CV risks in overweight and obese subjects have been assessed. Methods: Body mass index (BMI), waist circumference, waist-to-hip ratio, waist-to-height ratio (WHtR) and basal CV parameters were assessed in control ( N = 50), overweight ( N = 50) and obese ( N = 50) group subjects. Spectral analysis of HRV was performed in all these groups using Biopac system. Results: The basal CV parameters were significantly increased in overweight and obese subjects compared to controls. Low-frequency to high-frequency ratio (LF-HF ratio), marker of sympathovagal imbalance (SVI) was increased in overweight and obese subjects compared to controls. Total power (TP) and high frequency component expressed as normalized unit (Hfnu) which reflects the overall vagal drive to heart, was significantly decreased and low frequency component expressed as normalized unit (Lfnu) which reflects the sympathetic cardiac modulation, was significantly increased, in overweight and obese subjects compared to controls. These CV risks were predominately more in obese compared to overweight subjects. Conclusion: Increased resting heart rate, RPP and decreased HRV due to sympathetic activation and vagal withdrawal observed in overweight and obese subjects might contribute to the increased CV risk in these high risk populations.