目的·分析清晨高血压与心率及心率变异的关系，探讨交感激活与清晨高血压的关系。方法·选取2010年11月—2015年6月在高血压科门诊就诊的怀疑有高血压但尚未进行降压治疗的患者作为研究对象，分别进行24 h动态血压监测和心率变异性的时域和频域指标检测。清晨高血压定义为起床后2 h内收缩压平均值≥135 mmHg或舒张压≥85 mmHg。结果·596例研究对象中354例（59.4%）患有清晨高血压。Logistic回归分析结果显示，清晨高血压的患病风险随诊室坐位和卧位、24 h各时段的心率加快及诊室卧位低频心率变异的增大而增加（P＜0.01）；在调整了性别、年龄、体质量指数、吸烟、饮酒、空腹血糖及总胆固醇等影响因素后，24 h各时段心率及低频心率变异与清晨高血压的关联仍有统计学意义（P＜0.05）。结论·清晨高血压与心率加快及低频心率变异增大有关，提示清晨高血压与交感神经激活有关。

Objective · To analyze the association of morning hypertension with heart rate and heart rate variability and explore the association between sympathetic activity and morning hypertension. Methods · We recruited outpatients who visited the Department of Hypertension from Nov. 2010 to Jun. 2015 and were suspected of hypertension with no anti-hypertensive treatment. The 24 h ambulatory blood pressure was monitored and time domain and frequency domain indexes of heart rate variability were measured. The morning hypertension was defined as a mean systolic blood pressure of at least 135 mmHg or a mean diastolic blood pressure of at least 85 mmHg within 2 hours after getting up in the morning. Results · Of 596 subjects, 354 (59.4%) had morning hypertension. The Logistic regression analysis showed that the risk of morning hypertension increased with heart rates in sitting and supine positions, increased heart rate within 24 h and low frequency (LF) heart rate variability in supine position (P<0.01). After adjustments for sex, age, body mass index, cigarette smoking, alcohol consumption, fasting blood glucose, and serum total cholesterol, the associations of morning hypertension with 24 h heart rates and LF heart rate variability were still statistically significant (P<0.05). Conclusion · Morning hypertension is associated with increased heart rate and LF heart rate variability, indicating the association between morning hypertension and activated sympathetic system.