目的　探讨超重、肥胖儿童及代谢综合征（MS）患儿的心率减速力（DC）、心率加速力（AC）及心率变异性 （HRV）差异；体质指数（BMI）与DC、AC、HRV各指标间的相关性。方法　选择≥10岁的超重、肥胖儿童103例，其中诊断 为MS患儿48例；测定DC、AC、HRV各指标。结果　MS组DC值为（5.97±1.77）ms，低于非MS组的（7.93±1.56）ms； AC值为（－6.78±1.56）ms，高于非MS组的（－8.17±1.61）ms；HF值为335.2 ms²(157.03~659.33 ms²)，低于非MS组 的497.5 ms2(345.6~767.1 ms2)；BMI为（29.64±2.83）kg/m2，高于非MS组的（26.79±1.83）kg/m²，差异均有统计学 意义（P<0.05）。 超重、肥胖儿童BMI与DC呈显著负相关（r = －0.241， P=0.014），与AC呈正相关（r =0.199， P=0.044）。 结论　MS患儿的自主神经功能受损，表现为迷走神经张力降低。肥胖程度越高，迷走神经张力越低，机体对心脏的保护力 就越差，越易引起心血管疾病的发生。

Objectives　To explore the difference of heart rate deceleration capacity (DC), heart rate acceleration capacity (AC), and heart rate variability (HRV) among overweight children, obesity children, and metabolic syndrome (MS) children. The correlation between body mass index (BMI) and the indexes of DC, AC, and HRV was analyzed. Methods　One hundred three overweight and obesity children over 10 years old were selected. The levels of DC, AC, and HRV were detected in these children. Results　The level of DC (5.97±1.77 ms) in MS group was lower than that in non-MS group (7.93±1.56 ms); the level of AC (?6.78±1.56 ms) in MS group was higher than that in non-MS group (?8.17±1.61 ms²); the level of HF [335.2(157.03~659.33) ms²] in MS group was lower than that in non-MS group [497.5(345.6~767.1) ms²]; BMI (29.64±2.83 kg/m²) was higher than that in non-MS group (26.79±1.83 kg/m²) and the differences were statistically significant (P all < 0.05). The BMI in overweight and obesity children was negatively correlated with DC (r= ?0.241, P=0.014), and was positively correlated with AC (r=0.199, P=0.044). Conclusions　The autonomic nervous function of MS patients is impaired, and the vagus nerve tension is decreased. The protective force on the heart was weaker in the higher degree of overweight, obesity and lower vagus nerve tension, and thus it was the more likely to cause cardiovascular disease.