Significant role of the cardiopostural interaction in blood pressure regulation during standing

Abstract

Cardiovascular and postural control systems have been studied independently despite the increasing evidence showing the importance of cardiopostural interaction in blood pressure regulation. In this study, we aimed to assess the role of the cardiopostural interaction in relation to cardiac baroreflex in blood pressure regulation under orthostatic stress before and after mild exercise. Physiological variables representing cardiovascular control (heart rate and systolic blood pressure), lower limb muscle activation (electromyography), and postural sway (center of pressure derived from force and moment data during sway) were measured from 17 healthy participants (25 ± 2 yr, 9 men and 8 women) during a sit-to-stand test before and after submaximal exercise. The cardiopostural control (characterized by baroreflex-mediated muscle-pump effect in response to blood pressure changes, i.e., muscle-pump baroreflex) was assessed using wavelet transform coherence and causality analyses in relation to the baroreflex control of heart rate. Significant cardiopostural blood pressure control was evident counting for almost half of the interaction time with blood pressure changes that observed in the cardiac baroreflex (36.6-72.5% preexercise and 34.7-53.9% postexercise). Thus, cardiopostural input to blood pressure regulation should be considered when investigating orthostatic intolerance. A reduction of both cardiac and muscle-pump baroreflexes in blood pressure regulation was observed postexercise and was likely due to the absence of excessive venous pooling and a less stressed system after mild exercise. With further studies using more effective protocols evoking venous pooling and muscle-pump activity, the cardiopostural interaction could improve our understanding of the autonomic control system and ultimately lead to a more accurate diagnosis of cardiopostural dysfunctions. We examined the interaction between cardiovascular and postural control systems during standing before and after mild exercise. Significant cardiopostural input to blood pressure regulation was shown, suggesting the importance of cardiopostural integration when investigating orthostatic hypotension. In addition, we observed a reduction of baroreflex-mediated blood pressure regulation after exercise.

Cardio-postural interactions and muscle-pump baroreflex are severely impacted by 60-day bedrest immobilization

“…The LF band which was found to have the greatest engagement of the skeletal muscle-pump baroreflex (Table 3) is represented by the grey zone. At each time point, the coherence was evaluated based on the threshold of significant coherence obtained from a Monte Carlo simulation 20 . In each frequency band (HF, LF, and VLF), the number of frequency sub-band segments with significant coherence was calculated.…”

“…Supine-to-stand. A supine-to-stand (STS) test was used to evoke the cardio-postural control system [16][17][18][19][20]77 . Upon arrival at the testing room, the participants were placed in the supine position and instrumented for blood pressure (BP), electrocardiography (ECG), lower leg electromyography (EMG), and near-infrared spectroscopy (NIRS) of the left medial gastrocnemius.…”

Comparison of Autonomic Control of Blood Pressure During Standing and Artificial Gravity Induced via Short-Arm Human Centrifuge

“…Moreover, additional mechanisms that account for blood pressure regulation such as skeletal muscle pump (cardio-postural blood pressure regulation) shall also be investigated and compared in the future ( Garg et al, 2014 ; Verma et al, 2017a ; Xu et al, 2017 ). Furthermore, due to small sample size, the gender effect on blood pressure regulation and alteration in the dynamics of such behavior under artificial hypergravity remains to be understood.…”

“…The strength of closed loop heart rate-blood pressure interaction (RR↔SBP), signifying the feedforward (non-baroreflex) and feedback (baroreflex) controls of blood pressure was obtained using convergent cross mapping (CCM) similar to our previous work ( Verma et al, 2017b ; Xu et al, 2017 ). Prior to causality analysis, the evenly sampled continuous RR and SBP signals were resampled to 10 Hz.…”

Non-linear Heart Rate and Blood Pressure Interaction in Response to Lower-Body Negative Pressure

“…The interaction was quantified using a non-linear convergent cross mapping (CCM) method. The potential of CCM method in outlining the directional information flow between physiological signals has been demonstrated in the literature (Heskamp et al, 2014 ; Schiecke et al, 2015 , 2016 ; Verma et al, 2016 , 2017 ; Xu et al, 2017 ). Additionally, given the inherent non-linear nature of heart rate and blood pressure signals, the CCM method holds advantage toward unraveling underlying directional information flow compared to traditional Granger causality, which has been limited in effect with signals of non-linear nature (Schiecke et al, 2016 ).…”