Sex differences in vasoconstrictor reserve during 70 deg head-up tilt

S. S. Jarvis, J. P. Florian, M. J. Curren, J. A. Pawelczyk

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Women are generally recognized to be less orthostatically tolerant than men. We hypothesized that during head-up tilt (HUT), women would demonstrate less splanchnic vasoconstriction, leading to splanchnic pooling, lower blood pressure and lower orthostatic tolerance. Mean arterial blood pressure (MAP), heart rate (HR), cardiac output (, assessed by C2H2 rebreathing), stroke volume, splanchnic blood flow (SpBF, assessed by Indocyanine Green clearance) and vascular conductance (systemic, ; splanchnic, SpVC = SpBF/MAP; non-splanchnic, non-SpVC = SVC - SpVC) were measured during supine baseline conditions, 70 deg HUT and recovery in 14 healthy women (23 ± 6 years old; mean ± s.d.) and 16 men (23 ± 5 years old). The proportion of sexes surviving 45 min of HUT trended towards significance (χ2 = 2.92, P = 0.09). The MAP was lower in women than in men (supine, 77 ± 5 versus 86 ± 9 mmHg, P < 0.01; tilt, 72 ± 8 versus 83 ± 10 mmHg, P < 0.01), while HR and cardiac index (/body surface area) were not different between the sexes (heart rate supine, 66 ± 6 versus 64 ± 8 beats min-1; heart rate tilt, 96 ± 13 versus 94 ± 10 beats min-1; cardiac index supine, 3.8 ± 0.9 versus 3.7 ± 0.7 l min-1 m-2; cardiac index tilt, 2.7 ± 0.8 versus 2.3 ± 0.5 l min-1 m-2). The SpBF and SpVC were lower in women at rest but not during tilt (SpBF supine, 1174 ± 243 versus 1670 ± 391 ml min-1, P < 0.01; SpVC supine, 14.83 ± 3.61 versus 19.59 ± 4.95 ml min-1 mmHg-1, P < 0.01; SpBF tilt, 884 ± 300 versus 1094 ± 271 ml min-1; SpVC tilt, 13.14 ± 4.28 versus 14.82 ± 4.16 ml min-1 mmHg-1). However, in the women the SpVC did not decrease from baseline to tilt (ΔSpVC, in women, -1.70 ± 3.19 ml min-1 mmHg-1, n.s.; in men, -4.81 ± 3.44 ml min-1 mmHg-1, P < 0.01), suggesting a blunted vasoconstrictor response. In conclusion, women tended to have lower tilt-table tolerance associated with a smaller splanchnic vasoconstrictor reserve than men.

Original languageEnglish (US)
Pages (from-to)184-193
Number of pages10
JournalExperimental Physiology
Volume95
Issue number1
DOIs
StatePublished - Jan 2010

Fingerprint

Vasoconstrictor Agents
Sex Characteristics
Head
Viscera
Arterial Pressure
Heart Rate
Indocyanine Green
Body Surface Area
Vasoconstriction
Cardiac Output
Stroke Volume
Blood Vessels
Blood Pressure

All Science Journal Classification (ASJC) codes

  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)

Cite this

Jarvis, S. S. ; Florian, J. P. ; Curren, M. J. ; Pawelczyk, J. A. / Sex differences in vasoconstrictor reserve during 70 deg head-up tilt. In: Experimental Physiology. 2010 ; Vol. 95, No. 1. pp. 184-193.
@article{29c77c768dbb4a90846ccf01bd9d11cc,
title = "Sex differences in vasoconstrictor reserve during 70 deg head-up tilt",
abstract = "Women are generally recognized to be less orthostatically tolerant than men. We hypothesized that during head-up tilt (HUT), women would demonstrate less splanchnic vasoconstriction, leading to splanchnic pooling, lower blood pressure and lower orthostatic tolerance. Mean arterial blood pressure (MAP), heart rate (HR), cardiac output (, assessed by C2H2 rebreathing), stroke volume, splanchnic blood flow (SpBF, assessed by Indocyanine Green clearance) and vascular conductance (systemic, ; splanchnic, SpVC = SpBF/MAP; non-splanchnic, non-SpVC = SVC - SpVC) were measured during supine baseline conditions, 70 deg HUT and recovery in 14 healthy women (23 ± 6 years old; mean ± s.d.) and 16 men (23 ± 5 years old). The proportion of sexes surviving 45 min of HUT trended towards significance (χ2 = 2.92, P = 0.09). The MAP was lower in women than in men (supine, 77 ± 5 versus 86 ± 9 mmHg, P < 0.01; tilt, 72 ± 8 versus 83 ± 10 mmHg, P < 0.01), while HR and cardiac index (/body surface area) were not different between the sexes (heart rate supine, 66 ± 6 versus 64 ± 8 beats min-1; heart rate tilt, 96 ± 13 versus 94 ± 10 beats min-1; cardiac index supine, 3.8 ± 0.9 versus 3.7 ± 0.7 l min-1 m-2; cardiac index tilt, 2.7 ± 0.8 versus 2.3 ± 0.5 l min-1 m-2). The SpBF and SpVC were lower in women at rest but not during tilt (SpBF supine, 1174 ± 243 versus 1670 ± 391 ml min-1, P < 0.01; SpVC supine, 14.83 ± 3.61 versus 19.59 ± 4.95 ml min-1 mmHg-1, P < 0.01; SpBF tilt, 884 ± 300 versus 1094 ± 271 ml min-1; SpVC tilt, 13.14 ± 4.28 versus 14.82 ± 4.16 ml min-1 mmHg-1). However, in the women the SpVC did not decrease from baseline to tilt (ΔSpVC, in women, -1.70 ± 3.19 ml min-1 mmHg-1, n.s.; in men, -4.81 ± 3.44 ml min-1 mmHg-1, P < 0.01), suggesting a blunted vasoconstrictor response. In conclusion, women tended to have lower tilt-table tolerance associated with a smaller splanchnic vasoconstrictor reserve than men.",
author = "Jarvis, {S. S.} and Florian, {J. P.} and Curren, {M. J.} and Pawelczyk, {J. A.}",
year = "2010",
month = "1",
doi = "10.1113/expphysiol.2009.048819",
language = "English (US)",
volume = "95",
pages = "184--193",
journal = "Experimental Physiology",
issn = "0958-0670",
publisher = "Wiley-Blackwell",
number = "1",

}

Sex differences in vasoconstrictor reserve during 70 deg head-up tilt. / Jarvis, S. S.; Florian, J. P.; Curren, M. J.; Pawelczyk, J. A.

In: Experimental Physiology, Vol. 95, No. 1, 01.2010, p. 184-193.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Sex differences in vasoconstrictor reserve during 70 deg head-up tilt

AU - Jarvis, S. S.

AU - Florian, J. P.

AU - Curren, M. J.

AU - Pawelczyk, J. A.

PY - 2010/1

Y1 - 2010/1

N2 - Women are generally recognized to be less orthostatically tolerant than men. We hypothesized that during head-up tilt (HUT), women would demonstrate less splanchnic vasoconstriction, leading to splanchnic pooling, lower blood pressure and lower orthostatic tolerance. Mean arterial blood pressure (MAP), heart rate (HR), cardiac output (, assessed by C2H2 rebreathing), stroke volume, splanchnic blood flow (SpBF, assessed by Indocyanine Green clearance) and vascular conductance (systemic, ; splanchnic, SpVC = SpBF/MAP; non-splanchnic, non-SpVC = SVC - SpVC) were measured during supine baseline conditions, 70 deg HUT and recovery in 14 healthy women (23 ± 6 years old; mean ± s.d.) and 16 men (23 ± 5 years old). The proportion of sexes surviving 45 min of HUT trended towards significance (χ2 = 2.92, P = 0.09). The MAP was lower in women than in men (supine, 77 ± 5 versus 86 ± 9 mmHg, P < 0.01; tilt, 72 ± 8 versus 83 ± 10 mmHg, P < 0.01), while HR and cardiac index (/body surface area) were not different between the sexes (heart rate supine, 66 ± 6 versus 64 ± 8 beats min-1; heart rate tilt, 96 ± 13 versus 94 ± 10 beats min-1; cardiac index supine, 3.8 ± 0.9 versus 3.7 ± 0.7 l min-1 m-2; cardiac index tilt, 2.7 ± 0.8 versus 2.3 ± 0.5 l min-1 m-2). The SpBF and SpVC were lower in women at rest but not during tilt (SpBF supine, 1174 ± 243 versus 1670 ± 391 ml min-1, P < 0.01; SpVC supine, 14.83 ± 3.61 versus 19.59 ± 4.95 ml min-1 mmHg-1, P < 0.01; SpBF tilt, 884 ± 300 versus 1094 ± 271 ml min-1; SpVC tilt, 13.14 ± 4.28 versus 14.82 ± 4.16 ml min-1 mmHg-1). However, in the women the SpVC did not decrease from baseline to tilt (ΔSpVC, in women, -1.70 ± 3.19 ml min-1 mmHg-1, n.s.; in men, -4.81 ± 3.44 ml min-1 mmHg-1, P < 0.01), suggesting a blunted vasoconstrictor response. In conclusion, women tended to have lower tilt-table tolerance associated with a smaller splanchnic vasoconstrictor reserve than men.

AB - Women are generally recognized to be less orthostatically tolerant than men. We hypothesized that during head-up tilt (HUT), women would demonstrate less splanchnic vasoconstriction, leading to splanchnic pooling, lower blood pressure and lower orthostatic tolerance. Mean arterial blood pressure (MAP), heart rate (HR), cardiac output (, assessed by C2H2 rebreathing), stroke volume, splanchnic blood flow (SpBF, assessed by Indocyanine Green clearance) and vascular conductance (systemic, ; splanchnic, SpVC = SpBF/MAP; non-splanchnic, non-SpVC = SVC - SpVC) were measured during supine baseline conditions, 70 deg HUT and recovery in 14 healthy women (23 ± 6 years old; mean ± s.d.) and 16 men (23 ± 5 years old). The proportion of sexes surviving 45 min of HUT trended towards significance (χ2 = 2.92, P = 0.09). The MAP was lower in women than in men (supine, 77 ± 5 versus 86 ± 9 mmHg, P < 0.01; tilt, 72 ± 8 versus 83 ± 10 mmHg, P < 0.01), while HR and cardiac index (/body surface area) were not different between the sexes (heart rate supine, 66 ± 6 versus 64 ± 8 beats min-1; heart rate tilt, 96 ± 13 versus 94 ± 10 beats min-1; cardiac index supine, 3.8 ± 0.9 versus 3.7 ± 0.7 l min-1 m-2; cardiac index tilt, 2.7 ± 0.8 versus 2.3 ± 0.5 l min-1 m-2). The SpBF and SpVC were lower in women at rest but not during tilt (SpBF supine, 1174 ± 243 versus 1670 ± 391 ml min-1, P < 0.01; SpVC supine, 14.83 ± 3.61 versus 19.59 ± 4.95 ml min-1 mmHg-1, P < 0.01; SpBF tilt, 884 ± 300 versus 1094 ± 271 ml min-1; SpVC tilt, 13.14 ± 4.28 versus 14.82 ± 4.16 ml min-1 mmHg-1). However, in the women the SpVC did not decrease from baseline to tilt (ΔSpVC, in women, -1.70 ± 3.19 ml min-1 mmHg-1, n.s.; in men, -4.81 ± 3.44 ml min-1 mmHg-1, P < 0.01), suggesting a blunted vasoconstrictor response. In conclusion, women tended to have lower tilt-table tolerance associated with a smaller splanchnic vasoconstrictor reserve than men.

UR - http://www.scopus.com/inward/record.url?scp=74049122525&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=74049122525&partnerID=8YFLogxK

U2 - 10.1113/expphysiol.2009.048819

DO - 10.1113/expphysiol.2009.048819

M3 - Article

C2 - 19734174

AN - SCOPUS:74049122525

VL - 95

SP - 184

EP - 193

JO - Experimental Physiology

JF - Experimental Physiology

SN - 0958-0670

IS - 1

ER -