Michael (Mick) Leahy’s PhD Thesis Proposal

Title:“The effect of age and sex on the neurovascular and cardiovascular metaboreflex response”

Thesis Supervisor: Dr. Bill Sheel
Committee Members: Dr. Nisha Charkoudian, Dr. Glen Foster, Dr. Michael Koehle

Chair: Dr Cameron Mitchell

Abstract: The metaboreflex is a metabolically stimulated reflex initiated in contracting skeletal muscle. Accumulating metabolites stimulate group III/IV afferent fibers resulting in a sympathetically mediated pressor response; thereby causing vasoconstriction of the peripheral vasculature and an increase in arterial pressure. The respiratory muscles are able to evoke the same reflex. Women have an attenuated cardiovascular response to the metaboreflex stimulated from the limb and respiratory musculature. Reasons for this are not fully understood; however, it is possible circulating reproductive hormones (e.g. estrogen and progesterone) can the regulation of arterial pressure. The purpose of this thesis is to understand the mechanisms that explain male-female differences in the physiological responses to the respiratory muscle metaboreflex. A series of studies have been designed to observe the neurovascular and cardiovascular response to inspiratory muscle work, and can further our understanding of the effect of sex on the relationship between ventilation and the pressor reflex.