Heart autonomic function in overweight adolescents.

We compared factors associated with sympathetic cardiac activity in 70 male adolescents (34 obese and 36 with appropriate weight). In fasting we measured insulin, leptin, glucose, blood pressure, and heart rate variability by power spectral analysis. Obese adolescents had higher values for systolic blood pressure, insulin, leptin, low frequency/high frequency index (LF/HF); and lower for standard deviation of all the normal RR intervals, and total power. In the multiple regression analysis, factors associated with LF/HF index were leptin and systolic blood pressure (R2 = 0.18; P = 0.004 for the model). We concluded that higher sympathetic activity in obese adolescents is related to higher leptin and systolic blood pressure levels..