The Dynamics of Blood Flow Changes in Lower Limb Arteries During and Following Exercise in Humans
- 170 Downloads
In the steady state of dynamic muscular exercise in humans, blood flow to exercising muscles (̇QM) increases essentially linearly with respect to work rate and oxygen uptake (̇VO2). The profiles of the nonsteady state ̇QM response however are poorly understood, reflecting in large part the technical difficulties of accurately determining limb blood flow during periods of rapid change. Previous attempts to establish ̇QM kinetics have been hampered by uncertainties relating to the assumptions of the techniques. For example, the constant indicator infusion approach assumes that the indicator is uniformly dispersed throughout the flow pulse, and none is lost prior to reaching the sampling site. Also, “standard” Doppler estimates of flow from blood velocity assume both that the focus of the beam on to the vessel and the vessel geometry itself remain unchanged throughout the exercise — with no assurance, of course, that they are. The duplex Doppler technique, in contrast, is not prey to these assumptions as it (a) visualizes the vessel throughout the measurement and (b) determines the vessel diameter and therefore can establish blood flow in addition to velocity (3,4) — assuming only that the vessel cross-section is circular.
KeywordsBlood Velocity Common Femoral Artery Blood Flow Change Wingate Test Limb Blood Flow
Unable to display preview. Download preview PDF.
- 7.Shoemaker, J.K., L. Hodge, and R.L. Hughson, 1994, Cardiorespiratory kinetics and femoral artery blood velocity during dynamic knee extension exercise. J. Appl. Physiol. 11: 2625–2632.Google Scholar
- 8.Walloe, L., and J. Wesche, 1988, Time course and magnitude of blood flow changes in the human quadriceps muscles during and following rhythmic exercise. J. Physiol. (Lond.) 405: 257–273.Google Scholar
- 9.Withers, M., T. Hussain, M. Donlon, S.A. Ward, and B.J. Whipp, 1996, Pulmonary O2 uptake kinetics and femoral artery blood flow following high-intensity exercise in humans. Proc. Physiol. Soc., Feb. meeting, p,C23.Google Scholar