The acute inspiratory resistive load (IRL) may increase the respiratory pump contributes to hemodynamic responses during orthostatic stress. However, IRL effects on cerebrovascular and postural control interplay is unknown. Fourteen older women (65 ± 4 years) performed two orthostatic tests with spontaneous breathing through acute experimental (-9 cm.H2O) or sham load impedance (0 cmH2O) connected to a pneumotachograph for breath-by-breath recordings on a facemask. Both tests were executed on a force plate, for postural balance analysis, and electromyographic activity records of calf muscles. Blood pressure, middle cerebral artery blood velocity (MCAv), heart rate (HR), stroke volume (SV), and cardiac output (CO) were continuously recorded. IRL reduced postural instability in the first five seconds at orthostatic position compared to sham. Although the mean blood pressure and MCAv were similar in both conditions, IRL reduced the SV and CO drops, and time to recover MCAv. Therefore, IRL improved postural control, CO and MCAv responses during initial orthostasis.

中文翻译：

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老年妇女体位性应激期间呼吸泵对脑血管和姿势控制反应的贡献。

急性吸气阻力负荷（IRL）可能会增加呼吸泵，从而在体位性应激期间促进血液动力学反应。但是，IRL对脑血管和姿势控制相互作用的影响尚不清楚。14位年龄较大的女性（65±4岁）通过连接到呼吸速度描记器的急性实验（-9 cm.H2O）或假负荷阻抗（0 cmH2O）进行了自发性呼吸的两项体位测试，以在面罩上逐次呼吸记录。两种测试均在测力板上进行，用于姿势平衡分析和小腿肌肉的肌电活动记录。连续记录血压，大脑中动脉血流速度（MCAv），心率（HR），中风量（SV）和心输出量（CO）。与假手术相比，IRL减少了立位时头五秒钟的姿势不稳。尽管两种情况下的平均血压和MCAv相似，但IRL减少了SV和CO下降，并缩短了恢复MCAv的时间。因此，IRL在初始矫正过程中改善了姿势控制，CO和MCAv反应。