Heart rate variability in childhood obesity and the metabolic syndrom

Childhood obesity is considered as one of the most common illnesses threatening 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 these type of illnesses, which mostly showing clinical findings in adult age, are based in the childhood. Recent studies have shown that some disorders of cardiovascular autonomic nervous system can be observed in obese children, and it has been demonstrated that these disorders are one of the triggering factor for the coronary heart disease and hypertension. Also these disorders may contribute to the insulin resistance. Investigation of heart rate variability is one of the non-invasive technique in evaluating cardiovascular autonomic nervous system, and early detection of hypertension and coronary heart diseases. In this technique low frequency (LF) reflects sempatovagal activity, while high frequency (HF) shows vagal activity, and LF/HF rate means the sempatovagal balance. In our study 66 obese children and 40 healthy controls were investigated about heart rate variability. Metabolic syndrome risk factors were studied only in obese children. In obese children HF values were lower in obese children than controls (p=0.043, p<0.05). LF/HF rate was significantly high (p=0.000, p<0.05) but there was no statistically significant difference in LF values (p=0.790, p>0.05). 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 a consequence; our findings suggest that the vagal activity in obese children was decreased and the autonomical nervous system balance was changed in favour of sympathetic activity. Heart rate variability technique may be used in early detection of riskness obese children about hypertension and coronary heart disease. Additionally metabolic syndrome frequency was beyond the estimations.