Hemodynamic responses to an exercise stress test in Parkinson’s disease patients without orthostatic hypotension

Abstract

The presence of postganglionic sympathetic denervation is well established in Parkinson’s disease (PD). Denervation at cardiac and blood vessel sites may lead to abnormal cardiovascular and hemodynamic responses to exercise. The aim of the present investigation was to examine how heart rate (HR) and hemodynamics are affected by an exercise test in PD patients without orthostatic hypotension. Thirty individuals without orthostatic hypotension, 14 individuals with PD, and 16 age-matched healthy controls performed an exercise test on a cycle ergometer. Heart rate, blood pressure, and other hemodynamic variables were measured in a fasted state during supine rest, active standing, exercise, and supine recovery. Peak HR and percent of age-predicted maximum HR (HRmax) achieved were significantly blunted in PD (p < 0.05, p < 0.01). HR remained significantly elevated in PD during recovery compared with controls (p = 0.03, p < 0.05). Systolic, diastolic, and mean arterial pressures were significantly lower at multiple time-points during active standing in PD compared with controls. Systemic vascular resistance index (SVRI) decreased significantly at the onset of exercise in PD, and remained significantly lower during exercise and the first minute of supine recovery. End diastolic volume index (EDVI) was significantly lower in PD during supine rest and recovery. Our results indicate for the first time that normal hemodynamics are disrupted during orthostatic stress and exercise in PD. Despite significant differences in EDVI at rest and during recovery, and SVRI during exercise, cardiac index was unaffected. Our finding of significantly blunted HRmax and HR recovery in PD patients has substantial implications for exercise prescription and recovery guidelines.

Fatigability and Cardiorespiratory Impairments in Parkinson’s Disease: Potential Non-Motor Barriers to Activity Performance

“…The literature indicates that both performance fatigability and perceived fatigability are often elevated in people with PD. Studies providing insight into fatigability during whole-body activities in people with PD are presented in Table 1 [29][30][31][32][33][34][35][36][37][38][39][40]. When compared to healthy controls, it is consistently reported that people with PD demonstrate reduced distance walked and lower cardiorespiratory fitness [29,30,33,35,38,39].…”

“…When compared to healthy controls, it is consistently reported that people with PD demonstrate reduced distance walked and lower cardiorespiratory fitness [29,30,33,35,38,39]. Multiple reports of reduced performance during less demanding exercise protocols in people with PD compared to healthy controls [31,37,40,41] suggest these individuals are likely predisposed towards increased fatigability during less strenuous activities as well. Elevated perceived fatigability often occurs concomitantly with increased performance fatigability in people with PD.…”

“…While studies investigating peak oxygen consumption (VO 2 ) between people with PD and controls are not conclusive [29,30], most findings point to lower peak VO 2 in people with PD. Moreover, the literature widely reports reductions in various submaximal indices of aerobic function and substantial limitations in exercise performance in the PD population [29][30][31]33,35,[37][38][39][40][41]62]. Several factors are likely to contribute to low cardiorespiratory fitness in PD including cardiorespiratory alterations due to aging, physical inactivity, and cardiorespiratory impairments specific to the pathophysiology of PD.…”

“…The alteration in sympathetic activity is found to occur early in the disease process [97], sometimes even preceding the onset of clinically apparent motor symptoms [98,99], and increases in severity with disease progression [100]. Individuals with PD often fail to reach their age-predicted maximal heart rate (HR) at peak exercise [33,40,101]. Increased fatigability is often reported alongside decreased peak VO 2 and decreased peak HR in people with PD compared to healthy controls [35,38,39,62].…”

“…While the collective influence of these pathological alterations on hemodynamics and exercise performance is not completely described, reduced systolic blood (BP) pressure responses to exercise are commonly observed in people with PD [31,33,35,39,111]. For example, it was recently reported that, in comparison to healthy controls, systemic vascular resistance dropped more precipitously upon initiation of exercise in people with PD [40], suggesting that sympathetic control over vascular conductance may be reduced in members of this patient population. Additionally, blunted increases in systolic BP have been associated with increased fatigability [33] and reduced VO 2 in people with PD compared to healthy controls [35,39].…”