The Role of Heart Rate on the Associations Between Body Composition and Heart Rate Variability in Children With Overweight/Obesity: The ActiveBrains Project.

Abel Plaza-Florido,Pablo Molina-Garcia,Jairo H Migueles,Nathalie Michels,Jerzy Sacha,Jose Mora-Gonzalez,Maria Rodriguez-Ayllon,Rosa Maria Lozano,Socorro Navarrete,Cristina Cadenas-Sanchez,Irene Esteban-Cornejo,Francisco B Ortega

doi:10.3389/fphys.2019.00895

Abstract

BackgroundHeart rate variability (HRV) is negatively associated with body mass index and adiposity in several populations. However, less information is available about this association in children with overweight and obesity, especially severe/morbid obesity, taking into consideration the dependence of HRV on heart rate (HR).Objectives(1) to examine associations between body composition measures and HRV, (2) to study differences in HRV between children with overweight and severe/morbid obesity; and (3) to test whether relationships and differences tested in objectives 1 and 2, respectively are explained by the dependency of HRV on HR.MethodsA total of 107 children with overweight/obesity (58% boys, 10.03 ± 1.13 years) participated in this study. Body composition measures were evaluated by Dual-energy X-ray absorptiometry (DXA). HRV parameters were measured with Polar RS800CX®.ResultsBody composition measures were negatively associated with HRV indicators of parasympathetic activity (β values ranging from −0.207 to −0.307, all p < 0.05). Children with severe/morbid obesity presented lower HRV values with respect to children with overweight/mild obesity in HRV parameters indicators of parasympathetic activity (p = 0.035). All associations disappeared after further adjustment for HR (all p > 0.05).ConclusionAll associations between adiposity/obesity and HRV could be explained by HR, suggesting a key confounding role of HR in HRV studies in children with weight disturbances.

Highlights

Childhood obesity is one of the major public health concerns worldwide (World Health Organization [WHO], 2017)
Body composition measures were negatively associated with heart rate variability (HRV) indicators of parasympathetic activity (β values ranging from −0.207 to −0.307, all p < 0.05)
Our study suggests that body composition (BC) measures are negatively associated with HRV parameters, indicators of parasympathetic activity (PA), but the associations found seem to be explained by mean heart rate (HR)

Summary

Introduction

Childhood obesity is one of the major public health concerns worldwide (World Health Organization [WHO], 2017). A negative association has been reported between several BC measures [i.e., fat mass and fat-free mass (Gutin et al, 2000), body weight, and waist circumference (WC) (RodríguezColón et al, 2011), and body mass index (BMI) (Birch et al, 2012)] with HRV parameters in time- and frequency-domain (hereinafter referred to as HRV parameters) either in children with normal weight (NW), overweight (OW), or obesity (OB). HRV strongly depends on heart rate (HR) (Sacha and Pluta, 2008; Sacha, 2013, 2014b) This dependency has been shown to be an important factor to consider when analyzing HRV associations with health outcomes (Trimmel et al, 2015), but previous studies have failed in considering this dependency. Less information is available about this association in children with overweight and obesity, especially severe/morbid obesity, taking into consideration the dependence of HRV on heart rate (HR)

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