Uzu T, Ishikawa K, Fujii T, Nakamura S, Inenaga T, Kimura G
Division of Nephrology, National Cardiovascular Center, Suita, Osaka, Japan.
Circulation. 1997 Sep 16;96(6):1859-62. doi: 10.1161/01.cir.96.6.1859.
Sodium restriction has been widely used for treatment of hypertension and renal diseases. Whether sodium restriction can transform the circadian rhythm of blood pressure from nondipper to dipper is examined.
Patients (n=42) with essential hypertension were maintained on a high-sodium diet (12 to 15 g of NaCl per day) and a low-sodium diet (1 to 3 g/d) for 1 week each. On the last day of each diet, blood pressures were measured noninvasively every hour for 24 hours with an automatic oscillometric device. Twenty-one patients were classified as non-sodium sensitive whereas 21 were classified as sodium sensitive on the basis of a > or = 10% change in 24-hour mean arterial pressure caused by sodium restriction. Nocturnal blood pressure fall was significant in the non-sodium sensitive subjects but not in sodium-sensitive subjects. There was a significant interaction between sodium restriction and nocturnal fall in blood pressure only in the sodium-sensitive subjects, indicating that the degree of the nocturnal fall was affected by sodium restriction. Furthermore, changes in the nocturnal fall induced by sodium restriction had a positive relationship with sodium sensitivity (r=.38, P<.02) and a negative relationship with the nocturnal fall before sodium restriction (r=-.75, P<.0001).
These findings show the difference in nocturnal fall in blood pressure between the non-sodium sensitive and sodium-sensitive types of essential hypertension. The diminished nocturnal fall, recognized in the sodium-sensitive type, is restored by sodium restriction, indicating that the circadian rhythm of blood pressure shifted from a nondipper to a dipper pattern. On the other hand, the nocturnal fall is not affected by sodium restriction in the non-sodium sensitive type, and the circadian rhythm remains of the dipper variety.
限钠已广泛用于治疗高血压和肾脏疾病。本研究旨在探讨限钠是否能使血压昼夜节律从非勺型转变为勺型。
42例原发性高血压患者分别接受高钠饮食（每日12至15克氯化钠）和低钠饮食（每日1至3克）各1周。在每种饮食的最后一天，使用自动示波装置每小时无创测量一次血压，持续24小时。根据限钠引起的24小时平均动脉压变化≥10%，将21例患者分类为非钠敏感型，21例患者分类为钠敏感型。非钠敏感型受试者夜间血压下降显著，而钠敏感型受试者则不然。仅在钠敏感型受试者中，限钠与夜间血压下降之间存在显著交互作用，表明夜间血压下降程度受限钠影响。此外，限钠引起的夜间血压下降变化与钠敏感性呈正相关（r = 0.38，P < 0.02），与限钠前的夜间血压下降呈负相关（r = -0.75，P < 0.0001）。
这些发现显示了原发性高血压非钠敏感型和钠敏感型之间夜间血压下降的差异。钠敏感型中观察到的夜间血压下降减弱通过限钠得以恢复，表明血压昼夜节律从非勺型转变为勺型。另一方面，非钠敏感型的夜间血压下降不受限钠影响，昼夜节律仍为勺型。
