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Updated: May 17, 2026
05:09
Long-Term Continuous Measurement of Renal Blood Flow in Conscious Rats
Published on: February 8, 2022
Duration until nighttime blood pressure fall indicates excess sodium retention
Michio Fukuda1, Takashi Uzu, Genjiro Kimura
1Department of Cardio-Renal Medicine and Hypertension, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan. m-fukuda@med.nagoya-cu.ac.jp
Chronobiology International
|November 8, 2012
Summary
Impaired sodium excretion causes persistent high blood pressure (BP). New research shows that medications like hydrochlorothiazide (HCTZ) and angiotensin receptor blockers (ARBs) shorten "dipping time" (DT), indicating improved sodium excretion and BP regulation.
Area of Science:
- Nephrology
- Cardiology
- Hypertension Research
Background:
- Impaired renal sodium excretion leads to sodium retention, preventing the normal nocturnal dip in blood pressure (BP).
- This persistent high BP continues until excess sodium is excreted.
- The "dipping time" (DT) is defined as the duration until nocturnal BP falls below 90% of the daytime average.
Purpose of the Study:
- To evaluate the effect of diuretics and angiotensin receptor blockers (ARBs) on "dipping time" (DT) and its relationship with sodium excretion.
- To establish DT as a potential indicator of sodium retention in hypertensive patients.
Main Methods:
- Reanalysis of data from two previous studies investigating the effects of hydrochlorothiazide (HCTZ) and ARBs on BP rhythm.
- Measurement of daytime urinary sodium excretion in relation to DT.
Main Results:
- Both HCTZ and ARBs were demonstrated to shorten the DT.
- A direct correlation was observed between a shortened DT and increased daytime urinary sodium excretion.
Conclusions:
- Diuretics and ARBs effectively reduce sodium retention and restore normal BP dipping patterns.
- DT serves as a valuable preliminary indicator for assessing sodium retention in clinical settings.
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