Kagelmann Niklas, Janke David, Maggioni Martina Anna, Gunga Hanns-Christian, Riveros Rivera Alain, Genov Magdalena, Noppe Alexandra, Habazettl Helmut, Bothe Tomas Lucca, Nordine Michael, Castiglioni Paolo, Opatz Oliver
Charité-Universitätsmedizin Berlin, Institute of Physiology, Center for Space Medicine and Extreme Environments Berlin, Berlin, Germany.
Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.
Front Physiol. 2023 May 15;14:1173171. doi: 10.3389/fphys.2023.1173171. eCollection 2023.
Orthostatic dysregulation occurs during exposure to an increased gravitational vector and is especially common upon re-entering standard Earth gravity (1 g) after an extended period in microgravity (0 g). External peripheral skin cooling (PSC) has recently been described as a potent countermeasure against orthostatic dysregulation during heat stress and in lower body negative pressure (LBNP) studies. We therefore hypothesized that PSC may also be an effective countermeasure during hyper-gravity exposure (+Gz). To investigate this, we designed a randomized short-arm human centrifuge (SAHC) experiment ("Coolspin") to investigate whether PSC could act as a stabilizing factor in cardiovascular function during +Gz. Artificial gravity between +1 g and +4 g was generated by a SAHC. 18 healthy male volunteers completed two runs in the SAHC. PSC was applied during one of the two runs and the other run was conducted without cooling. Each run consisted of a 10-min baseline trial followed by a +Gz step protocol marked by increasing g-forces, with each step being 3 min long. The following parameters were measured: blood pressure (BP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), cardiac output (CO). Furthermore, a cumulative stress index for each subject was calculated. +Gz led to significant changes in primary as well as in secondary outcome parameters such as HR, SV, TPR, CO, and BP. However, none of the primary outcome parameters (HR, cumulative stress-index, BP) nor secondary outcome parameters (SV, TPR, CO) showed any significant differences-whether the subject was cooled or not cooled. Systolic BP did, however, tend to be higher amongst the PSC group. In conclusion, PSC during +Gz did not confer any significant impact on hemodynamic activity or orthostatic stability during +Gz. This may be due to lower PSC responsiveness of the test subjects, or an insufficient level of body surface area used for cooling. Further investigations are warranted in order to comprehensively pinpoint the exact degree of PSC needed to serve as a useful countermeasure system during +Gz.
体位性调节障碍发生在重力矢量增加时，在长期处于微重力（0g）环境后重新进入标准地球重力（1g）时尤为常见。最近，外部外周皮肤冷却（PSC）被描述为热应激期间和下体负压（LBNP）研究中对抗体位性调节障碍的有效对策。因此，我们假设PSC在高重力暴露（+Gz）期间也可能是一种有效的对策。为了对此进行研究，我们设计了一项随机短臂人体离心机（SAHC）实验（“Coolspin”），以研究PSC在+Gz期间是否能作为心血管功能的稳定因素。SAHC产生了+1g至+4g之间的人工重力。18名健康男性志愿者在SAHC中完成了两次运行。在两次运行中的一次运行期间应用了PSC，另一次运行未进行冷却。每次运行包括一个10分钟的基线试验，随后是一个以增加重力为标志的+Gz阶梯方案，每个步骤持续3分钟。测量了以下参数：血压（BP）、心率（HR）、每搏输出量（SV）、总外周阻力（TPR）、心输出量（CO）。此外，还计算了每个受试者的累积应激指数。+Gz导致主要和次要结局参数（如HR、SV、TPR、CO和BP）发生显著变化。然而，无论是主要结局参数（HR、累积应激指数、BP）还是次要结局参数（SV、TPR、CO），在受试者是否接受冷却的情况下均未显示出任何显著差异。不过，PSC组的收缩压确实往往更高。总之，+Gz期间的PSC对+Gz期间的血流动力学活动或体位稳定性没有产生任何显著影响。这可能是由于受试对象的PSC反应性较低，或者用于冷却的体表面积水平不足。有必要进行进一步研究，以全面确定在+Gz期间作为有用对策系统所需的PSC的确切程度。
