Association between Cardiac Autonomic Control and Postural Control in Patients with Parkinson's Disease

Effects of trunk posture on cardiovascular and autonomic nervous systems: A pilot study

Objective: Although regular and moderate physical activity has been shown to improve the cardiovascular and autonomic nervous systems, little has been done to study the effects of postural changes in the movement on the heart and autonomic nervous system. To uncover changes in cardiac function and autonomic nerves induced by different underlying posture transitions and explore which trunk postures lead to chronic sympathetic activation. Therefore, this study investigated the effects of trunk posture on the cardiovascular and autonomic nervous systems. Methods: Twelve male subjects (age 24.7 ± 1.3) underwent this study. The non-invasive cardiac output NICOM monitoring equipment and the FIRSTBEAT system are used to dynamically monitor seven trunk postures in the sitting position simultaneously (neutral position, posterior extension, forward flexion, left lateral flexion, right lateral flexion, left rotation, right rotation). Each posture was maintained for 3 min, and the interval between each movement was 3 min to ensure that each index returned to the baseline level. Repeated analysis of variance test was used to compare and analyze the differences in human cardiac function, heart rate variability index, and respiratory rate under different postures. Results: Compared with the related indicators of cardiac output in a neutral trunk position: the cardiac index (CI) was significantly reduced in forwarding flexion and left rotation (3.48 ± 0.34 vs. 3.21 ± 0.50; 3.48 ± 0.34 vs. 3.21 ± 0.46, Δ L/(min/m2)) (p = 0.016, p = 0.013), cardiac output decreased significantly (6.49 ± 0.78 vs. 5.93 ± 0.90; 6.49 ± 0.78 vs. 6.00 ± 0.96, Δ L/min) (p = 0.006, p = 0.014), the stroke volume (stroke volume)decreased significantly (87.90 ± 15.10 vs. 81.04 ± 16.35; 87.90 ± 15.10 vs. 79.24 ± 16.83, Δ ml/beat) (p = 0.017, p = 0.0003); heart rate increased significantly in posterior extension (75.08 ± 10.43 vs. 78.42 ± 10.18, Δ beat/min) (p = 0.001); left rotation stroke volume index (SVI) decreased significantly (47.28 ± 7.97 vs. 46.14 ± 8.06, Δ ml/m2) (p = 0.0003); in the analysis of HRV-related indicators, compared with the neutral trunk position, the LF/HF of the posterior extension was significantly increased (1.90 ± 1.38 vs. 3.00 ± 1.17, p = 0.037), and the LF/HF of the forward flexion was significantly increased (1.90 ± 1.38 vs. 2.85 ± 1.41, p = 0.041), and the frequency-domain index LF/HF of right rotation was significantly increased (1.90 ± 1.38 vs. 4.06 ± 2.19, p = 0.008). There was no significant difference in respiratory rate (p > 0.05). Conclusion: A neutral trunk is the best resting position, and deviations from a neutral trunk position can affect the cardiovascular and autonomic nervous systems, resulting in decreased stroke volume, increased heart rate, and relative activation of sympathetic tone.

Objective Assessment of Cardiopostural Control and its Improvement after Yoga Training using Wii Balance Board and Heart Rate Variability in Young Girls with Flat Foot

Objective:

Bipedalism in humans demanded robust postural control systems to maintain balance and equilibrium during variety of volitional activities. Adaptive learning is a key characteristic of these control systems. Postural control and balance are associated with autonomic changes trying to maintain cardiovascular homeostasis during postural imbalances, which are specifically important in conditions like flat foot. Yoga training could help such cases to achieve better postural balance and autonomic state. Young adolescent girls with flat foot were studied in comparison to normal girls and flat foot boys.

Materials and Methods:

Sixteen girls and 11 boys with flat foot were subjected to posturography on Wii Balance Board connected wirelessly to PowerLab 15T. Wireless heart rate belt was used to acquire RR intervals. Vrikshasana was chosen as the suitable asana for 4-week training. Displacement of center of pressure (COP) and heart rate variability was analyzed using LabChart pro software before and after yoga training.

Results:

COP displacement in flat foot subjects is away from the center during erect stance and sway toward sides. Flat foot girls showed significant greater displacements and lesser correction after yoga compared to flat foot boys (P < 0.05). Flat foot girls also showed lesser recovery in LF% and RMSSD after 4-week yoga training.

Conclusion:

Studying the autonomic changes during voluntary postural imbalance on balance board provide real-time picture of internal state in flat foot individuals. The sympathetic dominance would account for preparedness and adaptation in postural control systems. This state improved with yoga training toward better cardiac vagal tone.