Leary A C, Donnan P T, MacDonald T M, Murphy M B
Department of Clinical Pharmacology and Therapeutics, National University of Ireland, Cork.
J Hypertens. 2000 Apr;18(4):405-10. doi: 10.1097/00004872-200018040-00008.
The aim of this study was to define the relationship between physical activity and the magnitude of the percentage fall in blood pressure at night (nocturnal dip).
We simultaneously monitored 24-h ambulatory blood pressure and measured physical activity by actigraphy in 434 patients. Blood pressure was measured every 20 min; the actigraph integrated an activity score every 10 s. Mean daytime and night-time activity were calculated from mean scores for the 15 min preceding each blood pressure measurement. Nocturnal dip in systolic and diastolic blood pressure (SBP and DBP) were regressed on mean (log-transformed) daytime activity. Mean night-time activity, age, gender, smoking status, body mass index (BMI) and clinic blood pressure were added into a multiple linear regression.
The patient group was heterogeneous in age, gender and mean 24-h blood pressure. Mean daytime activity level was significantly and positively associated with the magnitude of the nocturnal dip in both SBP and DBP. Increased night-time activity was significantly associated with a smaller nocturnal dip. Older patients had a smaller nocturnal dip per log unit daytime activity. Nocturnal dip in SBP was greater in males, and smaller in those taking antihypertensive medications. Smoking, BMI and clinical blood pressure level were not associated with the extent of the nocturnal dip after adjustment for other factors.
Daytime and night-time physical activity levels are independently and significantly predictive of the magnitude of the nocturnal dip in blood pressure. Variation in activity may confound interpretation of 24-h ambulatory blood pressure monitoring, and contribute to the poor reproducibility of dipper status.
本研究旨在明确身体活动与夜间血压下降百分比幅度（夜间血压下降）之间的关系。
我们对434例患者同时进行了24小时动态血压监测，并通过活动记录仪测量身体活动情况。每20分钟测量一次血压；活动记录仪每10秒整合一次活动得分。根据每次血压测量前15分钟的平均得分计算白天和夜间的平均活动量。将收缩压和舒张压的夜间血压下降情况对白天平均（对数转换后）活动量进行回归分析。将夜间平均活动量、年龄、性别、吸烟状况、体重指数（BMI）和诊室血压纳入多元线性回归分析。
患者组在年龄、性别和24小时平均血压方面存在异质性。白天平均活动水平与收缩压和舒张压的夜间血压下降幅度均呈显著正相关。夜间活动增加与较小的夜间血压下降显著相关。年龄较大的患者每增加一个对数单位的白天活动量，夜间血压下降幅度较小。男性收缩压的夜间血压下降幅度更大，服用降压药物的患者夜间血压下降幅度较小。在对其他因素进行调整后，吸烟、BMI和临床血压水平与夜间血压下降程度无关。
白天和夜间的身体活动水平可独立且显著地预测夜间血压下降幅度。活动量的变化可能会混淆对24小时动态血压监测结果的解读，并导致血压昼夜节律状态重复性差。
