Ekman Robert, Green David A, Scott Jonathon P R, Huerta Lluch Roger, Weber Tobias, Herssens Nolan
Riga Stradins University, Faculty of Medicine, Riga, Latvia.
Space Medicine Team (HRE-OM), European Astronaut Centre, European Space Agency, Cologne, Germany.
Front Physiol. 2022 Jul 4;13:898430. doi: 10.3389/fphys.2022.898430. eCollection 2022.
In an attempt to counteract microgravity-induced deconditioning during spaceflight, exercise has been performed in various forms on the International Space Station (ISS). Despite significant consumption of time and resources by daily exercise, including around one third of astronauts' energy expenditure, deconditioning-to variable extents-are observed. However, in future Artemis/Lunar Gateway missions, greater constraints will mean that the current high volume and diversity of ISS in-flight exercise will be impractical. Thus, investigating both more and multi-systems countermeasure approaches taking into account the novel mission profiles and the associated health and safety risks will be required, while also reducing resource requirements. One potential approach is to reduce mission exercise volume by the introduction of exercise-free periods, or "". Thus, we hypothesise that by evaluating the 'recovery' of the no-intervention control group of head-down-tilt bed rest (HDTBR) campaigns of differing durations, we may be able to define the relationship between unloading duration and the dynamics of functional recovery-of interest to future spaceflight operations within and beyond Low Earth Orbit (LEO)-including preliminary evaluation of the concept of exercise holidays. Hence, the aim of this literature study is to collect and investigate the post-HDTBR recovery dynamics of current operationally relevant anthropometric outcomes and physiological systems (skeletal, muscular, and cardiovascular) of the passive control groups of HDTBR campaigns, mimicking a period of 'exercise holidays', thereby providing a preliminary evaluation of the concept of 'exercise holidays' for spaceflight, within and beyond LEO. The main findings were that, although a high degree of paucity and inconsistency of reported recovery data is present within the 18 included studies, data suggests that recovery of current operationally relevant outcomes following HDTBR without exercise-and even without targeted rehabilitation during the recovery period-could be timely and does not lead to persistent decrements differing from those experienced following spaceflight. Thus, evaluation of potential exercise holidays concepts within future HDTBR campaigns is warranted, filling current knowledge gaps prior to its potential implementation in human spaceflight exploration missions.
为了对抗太空飞行期间微重力引起的身体机能衰退，国际空间站（ISS）上进行了各种形式的锻炼。尽管日常锻炼消耗了大量时间和资源，约占宇航员能量消耗的三分之一，但仍观察到不同程度的身体机能衰退。然而，在未来的阿尔忒弥斯/月球门户任务中，更多的限制意味着国际空间站目前高运动量和多样化的在轨锻炼将不切实际。因此，需要研究更多和多系统的对策方法，同时考虑到新的任务概况以及相关的健康和安全风险，还要减少资源需求。一种潜在的方法是通过引入无锻炼期（即“锻炼假期”）来减少任务锻炼量。因此，我们假设，通过评估不同持续时间的头低位卧床休息（HDTBR）活动中无干预对照组的“恢复情况”，我们或许能够确定卸载持续时间与功能恢复动态之间的关系，这对于低地球轨道（LEO）内外的未来太空飞行操作很重要，包括对锻炼假期概念的初步评估。因此，本文献研究的目的是收集并研究HDTBR活动中被动对照组在当前与操作相关的人体测量结果和生理系统（骨骼、肌肉和心血管系统）在HDTBR后的恢复动态，模拟一段“锻炼假期”，从而对LEO内外太空飞行的“锻炼假期”概念进行初步评估。主要发现是，尽管在所纳入的18项研究中，报告的恢复数据存在高度的匮乏和不一致，但数据表明，HDTBR后无锻炼（甚至在恢复期无针对性康复）情况下，当前与操作相关的结果的恢复可能是及时的，并且不会导致与太空飞行后经历的情况不同的持续下降。因此，有必要在未来的HDTBR活动中评估潜在的锻炼假期概念，在其可能应用于载人太空探索任务之前填补当前的知识空白。
