Background: The cardiovascular autonomic nervous system in obese children is one of the main initiators of coronary heart disease and hypertension and may have a close relationship with insulin resistance. Heart rate variability is one non-invasive method to assess the cardiovascular autonomic system. In this method, low frequency parameters reflect sympathovagal activity, high frequency parameters reflect vagal activity and the ratio of these parameters reflects sympathovagal balance.

Childhood obesity is considered as one of the most common illness threating public health. Obesity is one of the basic life threatening factor causing coronary heart diseases, hypertension, dyslipidemia, insulin resistance and metabolic syndrome. In detailed clinical studies it has been shown that this type of illness, which mostly showing clinical findings in adult age, is based in the childhood. The aim of this study was to evaluate the prevalence of metabolic syndrome in childhood obesity. Insulin resistance was found in 33 patients (50%); dyslipidemia in 49 patients (74%) and hypertension in 18 patients (27%). Metabolic syndrome was observed in 28 (42%) patients. As consequence, metabolic syndrome frequency was very high in obese children.