Variabilidade da frequência cardíaca em crianças e adolescentes brasileiros com transtorno do espectro autista e diferentes composições corporais

Abstract

Introduction: Autism Spectrum Disorder (ASD) has been associated with changes in body composition and a higher prevalence of overweight and obesity in children and adolescents, conditions that may negatively affect cardiovascular autonomic modulation. Objective: To investigate possible alterations in heart rate variability (HRV) in individuals with ASD according to different body composition classifications. Methods: Individuals with ASD and typically developing controls, aged between 7 and 16 years, were included and divided into subgroups according to body mass index (BMI). HRV was individually recorded for 15 minutes at rest. Results: The sample consisted of 110 participants, with 53 in the ASD group and 57 in the Control group, with no significant differences in age or anthropometric characteristics between groups. The use of psychotropic medications in the ASD group did not influence HRV indices. The ASD group showed reduced parasympathetic modulation, evidenced by lower Mean RR, RMSSD, and pNN50 values, as well as higher mean heart rate compared to the Control group. In BMI subgroup analyses, differences were more pronounced among participants with obesity, who also exhibited reductions in spectral indices (LF and HF), suggesting global impairment of autonomic modulation. Conclusion: Children and adolescents with ASD present autonomic dysfunction characterized by reduced parasympathetic activity and higher resting heart rate, particularly among those with excess body weight.