University of Western Ontario - Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Kinesiology

Supervisor

Dr. J Kevin Shoemaker

Delay of Publication

1

Abstract

This study tested whether long-term endurance training in older adults (ET; n = 15, 55 ± 4 years, relative VO2max = 50 ± 8 ml/kg/min) would alter cardiovagal control and preserve the cortical autonomic network compared to age-matched controls (CON; n = 15, 56 ± 4 years, relative VO2max = 37 ± 9 ml/kg/min). The hypothesis predicts 1) altered deactivation patterns of the ventral medial prefrontal cortex (vMPFC) in response to isometric hand grip (IHG) and 2) greater indices of cardiovagal control; a) increased baroreflex sensitivity at rest, b) greater heart rate change (ΔHR) and c) reductions in high frequency heart rate variability (ΔHF HRV) in the ET group. Functional magnetic resonance imaging was utilized to observe BOLD signal changes. There was no difference in measured indices of cardiovagal control between groups and both exhibited vMPFC deactivation with IHG. Overall, ET does not preserve cortical functional patterns in the older brain or enhance cardiovagal control compared to age-matched controls.