Publication Date

2018-04-06

Availability

Open access

Embargo Period

2018-04-06

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Kinesiology and Sport Sciences (Education)

Date of Defense

2018-03-30

First Committee Member

Joseph F. Signorile

Second Committee Member

Carlos Singer

Third Committee Member

Kevin A. Jacobs

Fourth Committee Member

Moataz Eltoukhy

Abstract

The aim of this investigation was to examine how heart rate, hemodynamics, and norepinephrine are affected by an exercise stress test in Parkinson’s disease (PD) patients. Fourteen individuals with PD (mean age, 68±12 yrs; Hoehn and Yahr stage 1-3) and sixteen healthy individuals (mean age, 66±7 yrs) performed a sub-maximal exercise test on a cycle ergometer. Heart rate (HR), norepinephrine (NE), blood pressure (BP), and other hemodynamic variables including cardiac output (Q), stroke volume (SV), systemic vascular resistance (SVR), and end-diastolic volume (EDV) were measured in a fasted state during supine rest, active standing, exercise, and supine recovery in all participants. Index values were used for all hemodynamic measures to account for differences in body size. Peak HR and percent of age-predicted maximum HR achieved were significantly blunted in PD patients compared to controls. HR remained significantly elevated in the PD group throughout recovery when compared to controls. Measures of BP, including systolic, diastolic, and mean arterial pressure were all significantly lower during active standing in PD compared to controls. Although differences in peak BP during exercise did not reach significance, average values for PD patients were lower than those seen in healthy controls. There were no significant differences in SV or Q at any time-points. SVR decreased to a significantly greater degree following the onset of exercise in PD and differences remained significant through two stages of the exercise test. Differences were also observed during the first minute of supine recovery. EDV was significantly lower in PD at nearly all time-points. As exercise intensity increased, this difference lost significance, but returned following a steep decrease during recovery. NE changed significantly from rest to exercise and recovery, but there were no significant differences between groups at any time-point. This was the first study to assess the effects of exercise stress testing on cardiac and vascular function in PD patients. Despite significant between-group differences in EDV at rest and during recovery, and SVR during exercise, cardiac index was not affected. Compensatory adjustments in HR and SV in PD patients may have accounted for the maintenance of blood circulation. The inability of our PD patients to reach their age-predicted target HR values is something that practitioners must take into account when prescribing high-intensity exercise, as using predicted values may overestimate true exercise capacity. Future studies are needed to determine how this affects participation, adherence, and physiological and performance adaptations to exercise training at different intensities.

Keywords

Parkinson's disease; hemodynamics; norepinephrine; cardiovascular; exercise; autonomic dysfunction

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