Cardiac Autonomic Adjustments During Baroreflex Test in Obese and Non-Obese Preadolescents

Abstract

BackgroundRecent studies have shown changes in cardiac autonomic control of obese preadolescents.ObjectiveTo assess the heart rate responses and cardiac autonomic modulation of obese preadolescents during constant expiratory effort.MethodsThis study assessed 10 obese and 10 non-obese preadolescents aged 9 to 12 years. The body mass index of the obese group was between the 95th and 97th percentiles of the CDC National Center for Health Statistics growth charts, while that of the non-obese group, between the 5th and 85th percentiles. Initially, they underwent anthropometric and clinical assessment, and their maximum expiratory pressures were obtained. Then, the preadolescents underwent a constant expiratory effort of 70% of their maximum expiratory pressure for 20 seconds, with heart rate measurement 5 minutes before, during and 5 minutes after it. Heart rate variability (HRV) and heart rate values were analyzed by use of a software.ResultsThe HRV did not differ when compared before and after the constant expiratory effort intra- and intergroup. The heart rate values differed (p < 0.05) during the effort, being the total variation in non-obese preadolescents of 18.5 ± 1.5 bpm, and in obese, of 12.2 ± 1.3 bpm.ConclusionThe cardiac autonomic modulation did not differ between the groups when comparing before and after the constant expiratory effort. However, the obese group showed lower cardiovascular response to baroreceptor stimuli during the effort, suggesting lower autonomic baroreflex sensitivity.

Heart rate variability to assess ventilatory threshold in ski‐mountaineering

“…Unfortunately, most of these studies were conducted in a laboratory and only two of them where "field" tests performed on a 10-m and 200-m flat running tracks (Cottin et al, 2007;Dourado et al, 2010), which is still a very controlled environment and is quite unlike ski-mountaineering. Moreover, the HRV methods chosen [time-domain analyses (Karapetian et al, 2008;Sales et al, 2011) or the Poincaré plot analysis (Paschoal & Fontana, 2011)] do not enable the determination of VT2 and thus are less applicable for performance in endurance sports. Conversely, a time-varying spectral-analysis method that computes high-frequency power spectral density (HFp) and the frequency associated with peak frequency in high-frequency range (fHF) has been used successfully to determine both VT1 and VT2 (Buchheit et al, 2007;Cottin et al, 2006Cottin et al, , 2007Mourot et al, 2012).…”

Cardiac Autonomic Functions May Be Influenced by Body Weight

“…Body mass index is one of the most important influential factors on HRV indices 3 . Recently, a research reported decreased HRV because of inflammatory processes in the obese population 4 .…”