Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness
Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness
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DOI：
10.1152/ajpheart.00555.2021
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发表时间：
2022-05-01
影响因子：
4.8
通讯作者：
Moralez，Gilbert
中科院分区：
文献类型：
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作者：
Hansen，Alexander B.;Amin，Sachin B.;Moralez，Gilbert
患有慢性高山病（CMS）和红细胞增多症的安第斯人与健康的安第斯人具有相似的最大摄氧量。因此，本研究旨在探索对流氧运输的潜在适应性，特别关注交感神经介导的非活动骨骼肌的血管收缩。在有 (CMS+,n= 7) 和无 (CMS−,n= 9) CMS 的安第斯山脉中，我们测量了休息时和稳态次最大循环运动期间的对流氧输送、血流动力学（通过动脉内导管测量动脉血压）和自主反应 [肌肉交感神经活动 (MSNA)] 的组成部分 [30% 和 60% 峰值功率输出 (PPO) 各 5 分钟]。骑自行车导致两个安第斯群体在两种工作负荷下的心率、心输出量和氧气输送量都有类似的增加。然而，在 60% PPO 时，CMS+ 的 Δ 总外周阻力减弱（CMS−，−10.7 ± 3.8 vs. CMS+，−4.9 ± 4.1 mmHg·L−1·min−1；P= 0.012；d= 1.5），这与更大的 Δ 前臂血管收缩（CMS−， −0.2 ± 0.6 与 CMS+ 相比，1.5 ± 1.3 mmHg·mL−1·min−1；P= 0.008；d= 1.7），Δ舒张压升高（CMS−，14.2 ± 7.2 与 CMS+ 相比，21.6 ± 4.2 mmHg；P= 0.023；d= 1.2) 与 CMS− 相比。有趣的是，虽然两组中 MSNA 突发频率在 PPO 为 30% 或 60% 时均没有变化，但 CMS+ 中 60% 时 Δ 突发发生率有所减弱（P= 0.028；d= 1.4）。这些发现表明，在患有红细胞增多症的安第斯人中，与 CMS− 相比，轻强度运动引起了相似的心血管和自主神经反应。此外，尽管外周阻力较高，但在中等强度运动期间仍能维持对流氧气输送。此外，运动过程中外周阻力的升高并不是由交感神经流出增多介导的，因此可能涉及其他神经和/或非神经因素。新的和值得注意的在次最大运动期间，患有红细胞增多症的安第斯山脉人维持对流氧输送。与健康的安第斯人相比，低强度运动引起了相似的心血管和自主神经反应。然而，在中等强度运动期间，我们观察到总外周阻力的减弱，这不能归因于肌肉交感神经活动的过度增加，表明其他神经和/或非神经机制可能有贡献。
Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS+,n= 7) and without (CMS−,n= 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS+had a blunted reduction in Δtotal peripheral resistance (CMS−, −10.7 ± 3.8 vs. CMS+, −4.9 ± 4.1 mmHg·L−1·min−1;P= 0.012;d= 1.5) that coincided with a greater Δforearm vasoconstriction (CMS−, −0.2 ± 0.6 vs. CMS+, 1.5 ± 1.3 mmHg·mL−1·min−1;P= 0.008;d= 1.7) and a rise in Δdiastolic blood pressure (CMS−, 14.2 ± 7.2 vs. CMS+, 21.6 ± 4.2 mmHg;P= 0.023;d= 1.2) compared with CMS−. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Δburst incidence was attenuated in CMS+(P= 0.028;d= 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS−. Furthermore, convective oxygen delivery is maintained during moderate-intensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.NEW & NOTEWORTHYDuring submaximal exercise, convective oxygen transport is maintained in Andeans suffering from polycythemia. Light intensity exercise elicited similar cardiovascular and autonomic responses compared with healthy Andeans. However, during moderate-intensity exercise, we observed a blunted reduction in total peripheral resistance, which cannot be ascribed to an exaggerated increase in muscle sympathetic nerve activity, indicating possible contributions from other neural and/or nonneural mechanisms.