School of Kinesiology, Western University, London, Ontario, Canada.
Faculty of Health Sciences, Western University, London, Ontario, Canada.
Physiol Rep. 2022 May;10(9):e15299. doi: 10.14814/phy2.15299.
The ability to regain control of balance is vital in limiting falls and injuries. Little is known regarding how the autonomic nervous system responds during recovery from balance perturbations of different intensities. The purpose of this study was to examine the cardiovascular response following a standing balance perturbation of varying intensities, quantify cardiac baroreflex sensitivity (cBRS) during standing perturbations, and to establish the stability of the cardiac baroreflex during quiet standing before and after balance disturbances. Twenty healthy participants experienced three different perturbation intensity conditions that each included 25 brief posteriorly-directed perturbations, 8-10 s apart. Three perturbation intensity conditions (low, medium, high) were given in random order. Physiological data were collected in quiet stance for 5 min before testing (Baseline) and again after the perturbation conditions (Recovery) to examine baroreflex stability. Beat-to-beat heart rate (HR) and systolic blood pressure (SBP) analysis post-perturbation indicated an immediate acceleration of the HR for 1-2 s, with elevated SBP 4-5 s post-perturbation. Heart rate changes were greatest in the medium (p = 0.035) and high (p = 0.012) intensities compared to low, while there were no intensity-dependent changes in SBP. The cBRS was not intensity-dependent (p = 0.402) but when perturbation conditions were combined, cBRS was elevated compared to Baseline (p = 0.046). The stability of baseline cBRS was excellent (ICC = 0.896) between quiet standing conditions. In summary, HR, but not SBP or cBRS were intensity-specific during postural perturbations. This was the first study to examine cardiovascular response and cBRS to postural perturbations.
重新获得平衡控制的能力对于限制跌倒和受伤至关重要。对于自主神经系统在不同强度的平衡干扰恢复过程中的反应，知之甚少。本研究的目的是检查不同强度的站立平衡干扰后的心血管反应，量化站立干扰期间的心脏压力反射敏感性（cBRS），并在平衡干扰前后安静站立时确定心脏压力反射的稳定性。二十名健康参与者经历了三种不同的扰动强度条件，每种条件包括 25 次短暂的向后指向扰动，间隔 8-10 秒。三种扰动强度条件（低、中、高）以随机顺序给出。在测试前（基线）和扰动条件后（恢复），在安静站立状态下收集 5 分钟的生理数据，以检查压力反射的稳定性。扰动后逐拍心率（HR）和收缩压（SBP）分析表明，HR 在 1-2 秒内立即加速，SBP 在扰动后 4-5 秒升高。中强度（p=0.035）和高强度（p=0.012）的心率变化明显大于低强度，而 SBP 没有强度依赖性变化。cBRS 与强度无关（p=0.402），但当扰动条件合并时，cBRS 与基线相比升高（p=0.046）。基线 cBRS 的稳定性极好（ICC=0.896），在安静站立条件之间。总之，HR 而不是 SBP 或 cBRS 在姿势扰动期间具有强度特异性。这是第一个研究姿势扰动后心血管反应和 cBRS 的研究。
