| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ENVIRONMENTAL, EXERCISE AND RESPIRATORY PHYSIOLOGY
1Department of Kinesiology, University of Waterloo, Waterloo, Ontario N2L 3G1; 2Department of Community Health Sciences, Brock University, St. Catharines, Ontario L2S 3A1; and 3School of Kinesiology, University of Western Ontario, London, Ontario, Canada N6A 3K7
Submitted 21 July 2003 ; accepted in final form 27 April 2004
Beat-by-beat estimates of total peripheral resistance (TPR) can be obtained from continuous measurements of cardiac output by using Doppler ultrasound and noninvasive mean arterial blood pressure (MAP). We employed transfer function analysis to study the heart rate (HR) and vascular response to spontaneous changes in blood pressure from the relationships of systolic blood pressure (SBP) to HR (SBP
HR), MAP to total peripheral resistance (TPR) and cerebrovascular resistance index (CVRi) (MAPTPR and MAPCVRi), as well as stroke volume (SV) to TPR in nine healthy subjects in supine and 45° head-up tilt positions. The gain of the SBPHR transfer function was reduced with tilt in both the low- (0.03–0.15 Hz) and high-frequency (0.15–0.35 Hz) regions. In contrast, MAPTPR transfer function gain was not affected by head-up tilt, but it did increase from low- to high-frequency regions. The phase relationships between MAPTPR were unaffected by head-up tilt, but, consistent with an autoregulatory system, changes in MAP were followed by directionally similar changes in TPR, just as observed for the MAPCVRi. The SVTPR had high coherence with a constant phase of 150–160°. Together, these data that showed changes in MAP preceded changes in TPR, as well as a possible link between SV and TPR, are consistent with complex interactions between the vascular component of the arterial and cardiopulmonary baroreflexes and intrinsic properties such as the myogenic response of the resistance arteries.
baroreflex; power spectral analysis; Doppler ultrasound; cardiac output; myogenic; autoregulation
This article has been cited by other articles:
|
|
 |
|
  P. N. Ainslie, S. Ogoh, K. Burgess, L. Celi, K. McGrattan, K. Peebles, C. Murrell, P. Subedi, and K. R. Burgess Differential effects of acute hypoxia and high altitude on cerebral blood flow velocity and dynamic cerebral autoregulation: alterations with hyperoxia J Appl Physiol, February 1, 2008; 104(2): 490 - 498. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. E. Watenpaugh, D. D. O'Leary, S. M. Schneider, S. M. C. Lee, B. R. Macias, K. Tanaka, R. L. Hughson, and A. R. Hargens Lower body negative pressure exercise plus brief postexercise lower body negative pressure improve post-bed rest orthostatic tolerance J Appl Physiol, December 1, 2007; 103(6): 1964 - 1972. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ichinose, S. Koga, N. Fujii, N. Kondo, and T. Nishiyasu Modulation of the spontaneous beat-to-beat fluctuations in peripheral vascular resistance during activation of muscle metaboreflex Am J Physiol Heart Circ Physiol, July 1, 2007; 293(1): H416 - H424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Kolb, D. L. Rotella, and H. M. Stauss Frequency response characteristics of cerebral blood flow autoregulation in rats Am J Physiol Heart Circ Physiol, January 1, 2007; 292(1): H432 - H438. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Parati, G. Mancia, M. D. Rienzo, P. Castiglioni, J. A. Taylor, and P. Studinger Point:Counterpoint: Cardiovascular variability is/is not an index of autonomic control of circulation J Appl Physiol, August 1, 2006; 101(2): 676 - 682. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. D. Steinback, D. D. O'Leary, J. Bakker, A. D. Cechetto, H. M. Ladak, and J. K. Shoemaker Carotid distensibility, baroreflex sensitivity, and orthostatic stress J Appl Physiol, July 1, 2005; 99(1): 64 - 70. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
