Influence of body mass index and waist-to-height ratio on cardiac autonomic responses in young adult healthy men

Purpose The present study aimed to verify the influence of body mass index (BMI) and waist-to-height ratio (WHR) on rest and recovery cardiac autonomic control in young healthy adults. Methods Eighteen eutrophic individuals with WHR < 0.5 (G1) and thirteen obese individuals with WHR ≥ 0.5 (G2) took part in this study. All participants visit to the laboratory. Anthropometric (body mass, height, and waist circumference), body composition, blood pressure at rest, and resting heart rate variability (HRV) measures were initially performed. After this, the participants were submitted to an incremental test on a treadmill, followed by a period of recovery with an HRV record (300 s active recovery + 300 s passive recovery). Results The parasympathetic indexes of HRV (RMSSD and lnHF) were lower in G2 in comparison to G1 at rest (p < 0.05). During the recovery period, it was also observed in G2 lower values of RMSSD, lnHF, and HF (nu), but with higher values of LF (nu) and LF/HF (p < 0.05) when compared with G1. It was observed in G2 that lower RMSSD60 values were observed in some moments during active and passive recovery compared to G1 (p < 0.05). The other heart rate recovery indices did not differ between G2 and G1 (p > 0.05). Conclusion Thus, it was observed that obese individuals with WHR ≥ 0.5 presented a lower rest and recovery vagal activity and a higher recovery sympathetic activity, indicating a cardiac autonomic dysfunction.