Hemodynamic Responses at the Onset of Handgrip Exercise in Patients with Parkinson Disease
Authors: Sabino‐Carvalho Jeann L. , Samora Milena , Teixeira André L. , Vianna Lauro C. 
Published: June 2021

Parkinson's disease (PD) is becoming a very prevalent condition among older people and physical exercise has been used as coping strategy for PD progress. Thus, a better understanding of hemodynamic responses to exercise in this population is still warranty. At the onset of isometric handgrip (IHG) exercise there is an increase in blood pressure (BP) and a fall in the total peripheral resistance (TPR) in healthy young subjects. This immediate fall of TPR was blocked by systemic intravenous infusion of muscarinic receptors antagonists, an indication of a cholinergic mechanism. Since PD also affects cholinergic neurons in the central nervous system, we hypothesized that patients with PD would present blunted hemodynamic responses at the onset of IHG exercise. Based on this background, we sought to investigate the immediate hemodynamic response at the onset of IHG exercise in patients with PD, as well as in young and older subjects in order to control for any aging effect. Twelve patients with PD (67±3 yrs, 171±2 cm, 74±2 kg), ten aged‐matched control (66 ±2 yrs, 171±3 cm, 75±4 kg) and ten male young subjects (21±0.5 yrs, 178±2 cm, 79±3kg) were enrolled. Mean BP, systolic volume (SV), heart rate (HR), cardiac output (CO) and total peripheral resistance (TPR) were measured in a beat‐to‐beat basis by using finger photoplethysmography and Modelflow method. Then, beat‐to‐beat mean BP, HR, SV, CO, and TPR during exercise were linearly interpolated at 1 Hz and expressed as a change from rest on a second‐by‐second basis. Additionally, the area under the curve (AUC) was calculated to summarize the hemodynamic response to exercise. After a rest period of eight minutes, each subject performed twenty seconds of isometric handgrip exercise at 40% of MVC. Patients with PD had similar pressor responses to IHG exercise compared to older subjects (AUC: 154±5 vs. 171±6 mmHg/s, P = 0.58 for PD and older) and augmented compared to young (AUC: 48±2 mmHg/s, P < 0.05) with the progressive increase in mean BP over the 20s of IHG exercise being significantly [(PD +0±0.5 mmHg at 3s, +10±1 mmHg at 10s and +12±1 mmHg at 20s), (aged; +0 ±1 mmHg at 3s, +9±2 mmHg at 10s and +17±2 mmHg at 20s) and (young; +1±2 mmHg at 3s, +2±1 mmHg at 10s and +6±2 mmHg at 20s). Patients with PD had similar responses of IHG‐induced fall in TPR compared to older subjects (AUC: −14 ± 8 mmHg.l.min−1.s vs. −4±15 mmHg.l.min−1.s, P=0.52 for PD and older) and attenuated compared to young subjects (AUC: −56±10 mmHg.l.min−1.s, P<0.05). No differences were observed between groups for the handgrip evoked a increase in HR. SV and CO responses to handgrip were lower in patients with PD and older compared to young subjects (AUC: 222±5 vs. 105±3 vs. 113±1 l.min−1.s−1 for young, aged and PD, respectively; and 29±1 vs. 13±0.1 vs. 14±0.2 ml/s for young, aged and PD, respectively; both P<0.05). Our results shows that the hemodynamic responses at the onset of isometric handgrip exercise are preserved in patients with PD compared to older subjects and impaired when compared to young subjects. Overall, these findings suggest that the cholinergic mechanism may be compromised with aging.Support or Funding InformationCNPq, FAPDF and CAPES.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.