Hemodynamic Responses to an Exercise Stress Test in Parkinson's Disease Patients without Orthostatic Hypotension.

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. Fourteen individuals with PD and sixteen age-matched healthy controls performed an exercise test on a cycle ergometer. HR, 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<.05, p<.01). HR remained significantly elevated in PD during recovery compared to controls (p=.03, p<.05). Systolic, diastolic, and mean arterial pressures were significantly lower at multiple time-points during active standing in PD compared to controls. Systemic vascular resistance (SVR) 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 (EDV) 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 EDV at rest and during recovery, and SVR during exercise, cardiac index was not affected. Our finding of significantly blunted HRmax and HR recovery in PD patients has substantial implications for exercise prescription and recovery guidelines.