Abstract
Background: Obesity adversely affects the homeostasis of a person through a combination of impairments to multiple physiological mechanisms. Autonomic functions are proposed to be in the core of different aspects of health and well-being.

Aims and Objectives: The objective of this study was to assess the impact of body composition and anthropometry on heart rate variability (HRV) in different age groups of adults.

Materials and Methods: A total of 140 healthy adults were randomly selected for this cross-sectional observational study. They were divided into three groups based on the age distributions: Group 1: 18–30 years (n = 51); Group 2: 31–45 years (n = 47); and Group 3: 46–60 years (n = 42). Following assessments were done in all the participants in three groups: Anthropometric measurements, body composition analysis based on the principle of bioelectric impedance, and HRV. One-way analysis of variance followed by post hoc analysis was done for intergroup comparisons and Spearman’s correlation was done to find the correlation coefficients between HRV characteristics and anthropometric measurements and body composition characteristics. P < 0.05 was considered as statistically significant.

Results: The body mass index (BMI), waist circumference (WC), waist/hip ratio (WHR), body fat%, visceral fat%, and very low frequency (VLF) were found to be increasing, whereas high frequency (HF) and total power were decreasing with age. BMI, WC, fat mass, subcutaneous fat (whole body)%, and visceral fat% were significantly correlated with frequency domain characteristics of HRV. The HF and total power of HRV were negatively correlated with BMI, WC, body fat%, and visceral fat%. In addition, the significant positive correlation between LF/HF ratio and WC and visceral fat% would point to the adverse effect of central adiposity and visceral fat on sympathovagal balance.

Conclusion: These results reflected parasympathetic withdrawal and sympathetic predominance with increased adiposity, associated with aging.

Key words: Body Composition; Anthropometry; Heart Rate Variability; Autonomic; Aging; Obesity