Muscle blood flow, hypoxia, and hypoperfusion

Michael Joseph Joyner, Darren P. Casey

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Blood flow increases to exercising skeletal muscle, and this increase is driven primarily by vasodilation in the contracting muscles. When oxygen delivery to the contracting muscles is altered by changes in arterial oxygen content, the magnitude of the vasodilator response to exercise changes. It is augmented during hypoxia and blunted during hyperoxia. Because the magnitude of the increased vasodilation during hypoxic exercise tends to keep oxygen delivery to the contracting muscles constant, we have termed this phenomenon "compensatory vasodilation." In a series of studies, we have explored metabolic, endothelial, and neural mechanisms that might contribute to compensatory vasodilation. These include the contribution of vasodilating substances like nitric oxide (NO) and adenosine, along with altered interactions between sympathetic vasoconstriction and metabolic vasodilation. We have also compared the compensatory vasodilator responses to hypoxic exercise with those seen when oxygen delivery to contracting muscles is altered by acute reductions in perfusion pressure. A synthesis of our findings indicate that NO contributes to the compensatory dilator responses during both hypoxia and hypoperfusion, while adenosine appears to contribute only during hypoperfusion. During hypoxia, the NO-mediated component is linked to a ß-Adrenergic receptor mechanism during lower intensity exercise, while another source of NO is engaged at higher exercise intensities. There are also subtle interactions between a-Adrenergic vasoconstriction and metabolic vasodilation that influence the responses to hypoxia, hyperoxia, and hypoperfusion. Together our findings emphasize both the tight linkage of oxygen demand and supply during exercise and the redundant nature of the vasomotor responses to contraction.

Original languageEnglish (US)
Pages (from-to)852-857
Number of pages6
JournalJournal of Applied Physiology
Volume116
Issue number7
DOIs
StatePublished - Apr 1 2014

Fingerprint

Vasodilation
Muscles
Oxygen
Nitric Oxide
Hyperoxia
Vasoconstriction
Vasodilator Agents
Adenosine
Adrenergic Agents
Adrenergic Receptors
Hypoxia
Skeletal Muscle
Perfusion
Pressure

Keywords

  • Exercise
  • Hypoxia
  • Oxygen
  • Vasodilation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Medicine(all)

Cite this

Muscle blood flow, hypoxia, and hypoperfusion. / Joyner, Michael Joseph; Casey, Darren P.

In: Journal of Applied Physiology, Vol. 116, No. 7, 01.04.2014, p. 852-857.

Research output: Contribution to journalArticle

Joyner, Michael Joseph ; Casey, Darren P. / Muscle blood flow, hypoxia, and hypoperfusion. In: Journal of Applied Physiology. 2014 ; Vol. 116, No. 7. pp. 852-857.
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