Doctoral Examination: Neurocirculatory reflexive control and plasticity in healthy males exposed to hypoxia

Brooke Shafer, supervised by Dr. Glen Foster, will defend their dissertation titled “Neurocirculatory reflexive control and plasticity in healthy males exposed to hypoxia” in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Kinesiology.

An abstract for Brooke Shafer’s dissertation is included below.

Examinations are open to all members of the campus community as well as the general public.

If you would like to attend this virtual examination please contact the supervisor at glen.foster@ubc.ca to receive a zoom link.

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ABSTRACT

Exposure to low oxygen (hypoxia) and/or high carbon dioxide (hypercapnia) increases the activity of the sympathetic nervous system. Elevated sympathetic action potential activity from the nervous system can contribute to high blood pressures(BP). The purpose of this dissertation was to investigate how hypoxia and hypercapnia affects reflexive control of the sympathetic nervous system in healthy males. First, sympathetic responses to exercise are preserved following intermittent hypercapnic hypoxia. Next, lasting sympathetic activity following hypoxia is permitted because BP regulating sensors reset to higher operating points and there is increased contribution from large-amplitude sympathetic action potentials; however, the ability of the sympathetic nervous system to change BP is reduced during hypoxia and remains decreased in early recovery. Finally, blood flows easier during expiration and low lung volumes at rest. These findings provide evidence of how the sympathetic nervous system controls BP at rest and in response to blood gas changes.