A comparative assessment of two techniques for investigating initial cardiovascular reflexes under acute orthostatic stress

Caroline A. Rickards, David G. Newman

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)

Abstract

The physiological differences between active and passive changes in posture have been previously established. This study determined the extent of the differences in the initial cardiovascular responses to the passive head-up tilt (HUT) and the active squat-stand test (SST). Eleven females and 13 males underwent one + 75° HUT and one SST. Beat-to-beat diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were determined non-invasively. Data were recorded 10 s prior to (control) and 30 s after tilt or stand (event). Blood pressure and HR responses were analysed by calculating the deviation from control at 10 s (T10), 20 s (T20) and 30 s (T30) after the onset of each test. The DBP response (reflecting changes in systemic vascular resistance) at T10 was -10 (2) mmHg [mean (SEM)] for the HUT and -25 (2) mmHg for the SST (P < 0.01). DBP returned to control levels by T30 for the HUT, but remained depressed for the SST. MAP responses directly reflected these changes in DBP. HR significantly increased from control values (P < 0.001) for the HUT [+ 14 (1) bpm] and the SST [+ 16 (1) bpm], and remained elevated for the entire 30-s period for both tests. This study demonstrates that although the magnitude of the initial blood pressure decrease is greater for the active SST compared with the passive HUT, the reflex compensatory response is no different, making the SST a greater challenge for the cardiovascular reflexes.

Original languageEnglish
Pages (from-to)449-457
Number of pages9
JournalEuropean Journal of Applied Physiology
Volume90
Issue number5-6
DOIs
Publication statusPublished - 1 Nov 2003

Keywords

  • Blood pressure
  • Cardiovascular
  • Gravity
  • Orthostasis
  • Orthostatic challenge

Cite this

@article{f070b96651344141af7b19e78d0f17af,
title = "A comparative assessment of two techniques for investigating initial cardiovascular reflexes under acute orthostatic stress",
abstract = "The physiological differences between active and passive changes in posture have been previously established. This study determined the extent of the differences in the initial cardiovascular responses to the passive head-up tilt (HUT) and the active squat-stand test (SST). Eleven females and 13 males underwent one + 75° HUT and one SST. Beat-to-beat diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were determined non-invasively. Data were recorded 10 s prior to (control) and 30 s after tilt or stand (event). Blood pressure and HR responses were analysed by calculating the deviation from control at 10 s (T10), 20 s (T20) and 30 s (T30) after the onset of each test. The DBP response (reflecting changes in systemic vascular resistance) at T10 was -10 (2) mmHg [mean (SEM)] for the HUT and -25 (2) mmHg for the SST (P < 0.01). DBP returned to control levels by T30 for the HUT, but remained depressed for the SST. MAP responses directly reflected these changes in DBP. HR significantly increased from control values (P < 0.001) for the HUT [+ 14 (1) bpm] and the SST [+ 16 (1) bpm], and remained elevated for the entire 30-s period for both tests. This study demonstrates that although the magnitude of the initial blood pressure decrease is greater for the active SST compared with the passive HUT, the reflex compensatory response is no different, making the SST a greater challenge for the cardiovascular reflexes.",
keywords = "Blood pressure, Cardiovascular, Gravity, Orthostasis, Orthostatic challenge",
author = "Rickards, {Caroline A.} and Newman, {David G.}",
year = "2003",
month = "11",
day = "1",
doi = "10.1007/s00421-003-0852-0",
language = "English",
volume = "90",
pages = "449--457",
journal = "European Journal of Applied Physiology",
issn = "1439-6319",
publisher = "Springer-Verlag London Ltd.",
number = "5-6",

}

A comparative assessment of two techniques for investigating initial cardiovascular reflexes under acute orthostatic stress. / Rickards, Caroline A.; Newman, David G.

In: European Journal of Applied Physiology, Vol. 90, No. 5-6, 01.11.2003, p. 449-457.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - A comparative assessment of two techniques for investigating initial cardiovascular reflexes under acute orthostatic stress

AU - Rickards, Caroline A.

AU - Newman, David G.

PY - 2003/11/1

Y1 - 2003/11/1

N2 - The physiological differences between active and passive changes in posture have been previously established. This study determined the extent of the differences in the initial cardiovascular responses to the passive head-up tilt (HUT) and the active squat-stand test (SST). Eleven females and 13 males underwent one + 75° HUT and one SST. Beat-to-beat diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were determined non-invasively. Data were recorded 10 s prior to (control) and 30 s after tilt or stand (event). Blood pressure and HR responses were analysed by calculating the deviation from control at 10 s (T10), 20 s (T20) and 30 s (T30) after the onset of each test. The DBP response (reflecting changes in systemic vascular resistance) at T10 was -10 (2) mmHg [mean (SEM)] for the HUT and -25 (2) mmHg for the SST (P < 0.01). DBP returned to control levels by T30 for the HUT, but remained depressed for the SST. MAP responses directly reflected these changes in DBP. HR significantly increased from control values (P < 0.001) for the HUT [+ 14 (1) bpm] and the SST [+ 16 (1) bpm], and remained elevated for the entire 30-s period for both tests. This study demonstrates that although the magnitude of the initial blood pressure decrease is greater for the active SST compared with the passive HUT, the reflex compensatory response is no different, making the SST a greater challenge for the cardiovascular reflexes.

AB - The physiological differences between active and passive changes in posture have been previously established. This study determined the extent of the differences in the initial cardiovascular responses to the passive head-up tilt (HUT) and the active squat-stand test (SST). Eleven females and 13 males underwent one + 75° HUT and one SST. Beat-to-beat diastolic blood pressure (DBP), systolic blood pressure (SBP), mean arterial pressure (MAP) and heart rate (HR) were determined non-invasively. Data were recorded 10 s prior to (control) and 30 s after tilt or stand (event). Blood pressure and HR responses were analysed by calculating the deviation from control at 10 s (T10), 20 s (T20) and 30 s (T30) after the onset of each test. The DBP response (reflecting changes in systemic vascular resistance) at T10 was -10 (2) mmHg [mean (SEM)] for the HUT and -25 (2) mmHg for the SST (P < 0.01). DBP returned to control levels by T30 for the HUT, but remained depressed for the SST. MAP responses directly reflected these changes in DBP. HR significantly increased from control values (P < 0.001) for the HUT [+ 14 (1) bpm] and the SST [+ 16 (1) bpm], and remained elevated for the entire 30-s period for both tests. This study demonstrates that although the magnitude of the initial blood pressure decrease is greater for the active SST compared with the passive HUT, the reflex compensatory response is no different, making the SST a greater challenge for the cardiovascular reflexes.

KW - Blood pressure

KW - Cardiovascular

KW - Gravity

KW - Orthostasis

KW - Orthostatic challenge

UR - http://www.scopus.com/inward/record.url?scp=0345531041&partnerID=8YFLogxK

U2 - 10.1007/s00421-003-0852-0

DO - 10.1007/s00421-003-0852-0

M3 - Article

VL - 90

SP - 449

EP - 457

JO - European Journal of Applied Physiology

JF - European Journal of Applied Physiology

SN - 1439-6319

IS - 5-6

ER -