Isometric handgrip (IHG) is used to assess sympathetic nervous system responses to exercise and may be useful at predicting hypertension in both pregnant and non-pregnant populations. We have previously observed altered sympathetic nervous system control of blood pressure in late pregnancy. Therefore, we measured muscle sympathetic nerve activity (MSNA) and blood pressure during muscle metaboreflex activation (IHG) in normotensive pregnant women in the third trimester compared to healthy non-pregnant women. Nineteen pregnant (32±3wks gestation) and fourteen non-pregnant women were matched for age, non/pre-pregnant BMI, and parity. MSNA (microneurography), heart rate (ECG), and arterial blood pressure (Finometer) were continuously recorded during ten minutes of rest, and then during two-minutes of IHG at 30% of maximal voluntary contraction, and two-minutes of post-exercise circulatory occlusion (PECO). Baseline SNA was elevated in pregnant (41±11 bursts/min) compared to non-pregnant women (27 ± 9 bursts/minute; p=0.005); however, the sympathetic baroreflex gain and neurovascular transduction were not different between groups (p=0.62 and p=0.32, respectively). During IHG and PECO there was no significant differences in the pressor response (∆MAP) during IHG and PECO was not different between groups (p=0.25, main effect of group) nor the sympathetic response (interaction effect: p=0.16, 0.25, and 0.27 for burst frequency, burst incidence, and total SNA respectively). These data suggest that pregnant women who have maintained sympathetic baroreflex and neurovascular transduction also have similar sympathetic and pressor responses during exercise.

中文翻译：

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在正常血压的孕妇中，妊娠中期交感肌代谢反射没有差异。

等距把手（IHG）用于评估运动对交感神经系统的反应，可能有助于预测孕妇和非孕妇人群的高血压。我们以前曾观察到妊娠晚期交感神经系统对血压的控制改变。因此，与健康的非孕妇相比，我们在妊娠晚期的血压正常孕妇中测量了肌肉交感神经激活（IHG）期间的肌肉交感神经活动（MSNA）和血压。匹配了19名孕妇（妊娠32±3周）和14名非孕妇的年龄，非/孕前BMI和胎次。在休息10分钟后连续记录MSNA（微神经造影），心率（ECG）和动脉血压（Finometer），然后在IHG 2分钟内以最大自愿收缩量的30％记录2分钟，和运动后2分钟的循环闭塞（PECO）。与未怀孕的女性（27±9突增/分钟； p = 0.005）相比，孕妇的基线SNA升高（41±11突增/分钟）。但是，各组的交感神经反射反射增益和神经血管传导没有差异（分别为p = 0.62和p = 0.32）。在IHG和PECO期间，各组之间的升压反应（∆MAP）均无显着差异（p = 0.25，组的主要作用），也没有交感反应（交互作用：p = 0.16，0.25，和0.27，分别是突发频率，突发发生率和总SNA）。这些数据表明，保持交感神经反射和神经血管转导的孕妇在运动过程中也具有相似的交感神经和压力反应。