Morning increase in whole blood viscosity: A consequence of a homeostatic nocturnal haemodynamic pattern

M. I. Talan, B. T. Engel

Research output: Contribution to journalArticle

Abstract

In a series of studies, we have shown that in non-human primates there is a consistent overnight fall in cardiac output and central venous pressure, and a rise in total peripheral resistance. This haemodynamic pattern is associated with a higher haematocrit level in the morning suggesting that these changes in the circulation are homeostatic adjustments to a nighttime fall in plasma volume. The present study was designed to test the hypothesis that in the morning whole blood viscosity also is higher. Whole blood viscosity was measured at shear rates of 450, 225, 90, 45, and 22.5 s-1 in each of six monkeys, on four occasions, at 2-week intervals, at 17.00 and 09.00 h the next morning. The average haematocrit was 4.2% higher in the morning than in the previous evening (P <0.01). Viscosity decreased monotonically at progressively higher shear rates but was always significantly higher in the morning than in the evening (P <0.01 at all shear rates). When viscosity was adjusted by covarying for haematocrit level, the morning/evening differences became non-significant. However, the morning/evening differences in linear trend of shear stress as a function of shear rate persisted. These findings add further support to our hypothesis that the nocturnal haemodynamic pattern in non-human primates is related to a reduction in plasma volume, and they also suggest that the morning rise in haematocrit is a major contributing factor to the elevated viscosity.

Original languageEnglish (US)
Pages (from-to)179-183
Number of pages5
JournalActa Physiologica Scandinavica
Volume147
Issue number2
StatePublished - 1993
Externally publishedYes

Fingerprint

Blood Viscosity
Hematocrit
Hemodynamics
Viscosity
Plasma Volume
Primates
Central Venous Pressure
Cardiac Output
Vascular Resistance
Haplorhini

Keywords

  • Diurnal
  • Haemodynamics
  • Plasma volume

ASJC Scopus subject areas

  • Physiology

Cite this

Morning increase in whole blood viscosity : A consequence of a homeostatic nocturnal haemodynamic pattern. / Talan, M. I.; Engel, B. T.

In: Acta Physiologica Scandinavica, Vol. 147, No. 2, 1993, p. 179-183.

Research output: Contribution to journalArticle

@article{de3a02034f264696821ac346d17ec467,
title = "Morning increase in whole blood viscosity: A consequence of a homeostatic nocturnal haemodynamic pattern",
abstract = "In a series of studies, we have shown that in non-human primates there is a consistent overnight fall in cardiac output and central venous pressure, and a rise in total peripheral resistance. This haemodynamic pattern is associated with a higher haematocrit level in the morning suggesting that these changes in the circulation are homeostatic adjustments to a nighttime fall in plasma volume. The present study was designed to test the hypothesis that in the morning whole blood viscosity also is higher. Whole blood viscosity was measured at shear rates of 450, 225, 90, 45, and 22.5 s-1 in each of six monkeys, on four occasions, at 2-week intervals, at 17.00 and 09.00 h the next morning. The average haematocrit was 4.2{\%} higher in the morning than in the previous evening (P <0.01). Viscosity decreased monotonically at progressively higher shear rates but was always significantly higher in the morning than in the evening (P <0.01 at all shear rates). When viscosity was adjusted by covarying for haematocrit level, the morning/evening differences became non-significant. However, the morning/evening differences in linear trend of shear stress as a function of shear rate persisted. These findings add further support to our hypothesis that the nocturnal haemodynamic pattern in non-human primates is related to a reduction in plasma volume, and they also suggest that the morning rise in haematocrit is a major contributing factor to the elevated viscosity.",
keywords = "Diurnal, Haemodynamics, Plasma volume",
author = "Talan, {M. I.} and Engel, {B. T.}",
year = "1993",
language = "English (US)",
volume = "147",
pages = "179--183",
journal = "Acta Physiologica Scandinavica",
issn = "0370-839X",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Morning increase in whole blood viscosity

T2 - A consequence of a homeostatic nocturnal haemodynamic pattern

AU - Talan, M. I.

AU - Engel, B. T.

PY - 1993

Y1 - 1993

N2 - In a series of studies, we have shown that in non-human primates there is a consistent overnight fall in cardiac output and central venous pressure, and a rise in total peripheral resistance. This haemodynamic pattern is associated with a higher haematocrit level in the morning suggesting that these changes in the circulation are homeostatic adjustments to a nighttime fall in plasma volume. The present study was designed to test the hypothesis that in the morning whole blood viscosity also is higher. Whole blood viscosity was measured at shear rates of 450, 225, 90, 45, and 22.5 s-1 in each of six monkeys, on four occasions, at 2-week intervals, at 17.00 and 09.00 h the next morning. The average haematocrit was 4.2% higher in the morning than in the previous evening (P <0.01). Viscosity decreased monotonically at progressively higher shear rates but was always significantly higher in the morning than in the evening (P <0.01 at all shear rates). When viscosity was adjusted by covarying for haematocrit level, the morning/evening differences became non-significant. However, the morning/evening differences in linear trend of shear stress as a function of shear rate persisted. These findings add further support to our hypothesis that the nocturnal haemodynamic pattern in non-human primates is related to a reduction in plasma volume, and they also suggest that the morning rise in haematocrit is a major contributing factor to the elevated viscosity.

AB - In a series of studies, we have shown that in non-human primates there is a consistent overnight fall in cardiac output and central venous pressure, and a rise in total peripheral resistance. This haemodynamic pattern is associated with a higher haematocrit level in the morning suggesting that these changes in the circulation are homeostatic adjustments to a nighttime fall in plasma volume. The present study was designed to test the hypothesis that in the morning whole blood viscosity also is higher. Whole blood viscosity was measured at shear rates of 450, 225, 90, 45, and 22.5 s-1 in each of six monkeys, on four occasions, at 2-week intervals, at 17.00 and 09.00 h the next morning. The average haematocrit was 4.2% higher in the morning than in the previous evening (P <0.01). Viscosity decreased monotonically at progressively higher shear rates but was always significantly higher in the morning than in the evening (P <0.01 at all shear rates). When viscosity was adjusted by covarying for haematocrit level, the morning/evening differences became non-significant. However, the morning/evening differences in linear trend of shear stress as a function of shear rate persisted. These findings add further support to our hypothesis that the nocturnal haemodynamic pattern in non-human primates is related to a reduction in plasma volume, and they also suggest that the morning rise in haematocrit is a major contributing factor to the elevated viscosity.

KW - Diurnal

KW - Haemodynamics

KW - Plasma volume

UR - http://www.scopus.com/inward/record.url?scp=0027450382&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027450382&partnerID=8YFLogxK

M3 - Article

C2 - 8475744

AN - SCOPUS:0027450382

VL - 147

SP - 179

EP - 183

JO - Acta Physiologica Scandinavica

JF - Acta Physiologica Scandinavica

SN - 0370-839X

IS - 2

ER -