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A systematic review of literature was conducted to evaluate the effectiveness of passive countermeasures in ameliorating the cardiopulmonary and musculoskeletal effects of gravitational unloading on humans during spaceflight. This systematic review is the third of a series being conducted by the European Space Agency to evaluate the effectiveness of countermeasures to physiologic deconditioning during spaceflight. With future long-duration space missions on the horizon, it is critical to understand the effectiveness of existing countermeasures to promote astronaut health and improve the probability of future mission success. An updated search for studies examining passive countermeasures was conducted in 2021 to supplement results from a broader search conducted in 2017 for all countermeasures. Ground-based analogue and spaceflight studies were included in the search. A total of 647 articles were screened following removal of duplicates, of which 16 were included in this review. Data extraction and analysis, quality assessment of studies, and transferability of reviewed studies to actual spaceflight based on their bed-rest protocol were conducted using dedicated tools created by the Aerospace Medicine Systematic Review Group. Of the 180 examined outcomes across the reviewed studies, only 20 were shown to have a significant positive effect in favour of the intervention group. Lower body negative pressure was seen to significantly maintain orthostatic tolerance (OT) closer to baseline as comparted to control groups. It also was seen to have mixed efficacy with regards to maintaining resting heart rate close to pre-bed rest values. Whole body vibration significantly maintained many balance-related outcome measures close to pre-bed rest values as compared to control. Skin surface cooling and centrifugation both showed efficacy in maintaining OT. Centrifugation also was seen to have mixed efficacy with regards to maintaining VO2max close to pre-bed rest values. Overall, standalone passive countermeasures showed no significant effect in maintaining 159 unique outcome measures close to their pre-bed rest values as compared to control groups. Risk of bias was rated high or unclear in all studies due to poorly detailed methodologies, poor control of confounding variables, and other sources of bias (i.e. inequitable recruitment of participants leading to a higher male:female ratios). The bed-rest transferability (BR) score varied from 2–7, with a median score of 5. Generally, most studies had good BR transferability but underreported on factors such as control of sunlight or radiation exposure, diet, level of exercise and sleep-cycles. We conclude that: (1) Lack of standardisation of outcome measurement and methodologies has led to large heterogeneity amongst studies; (2) Scarcity of literature and high risk of bias amongst existing studies limits the statistical power of results; and (3) Passive countermeasures have little or no efficacy as standalone measures against cardiopulmonary and musculoskeletal deconditioning induced by spaceflight related to physiologic deterioration due to gravity un-loading. [ABSTRACT FROM AUTHOR]

The validity of venous ultrasound (V-US) for the diagnosis of deep vein thrombosis (DVT) during spaceflight is unknown and difficult to establish in diagnostic accuracy and diagnostic management studies in this context. We performed a systematic review of the use of V-US in the upper-body venous system in spaceflight to identify microgravity-related changes and the effect of venous interventions to reverse them, and to assess appropriateness of spaceflight V-US with terrestrial standards. An appropriateness tool was developed following expert panel discussions and review of terrestrial diagnostic studies, including criteria relevant to crew experience, in-flight equipment, assessment sites, ultrasound modalities, and DVT diagnosis. Microgravity-related findings reported as an increase in internal jugular vein (IJV) cross-sectional area and pressure were associated with reduced, stagnant, and retrograde flow. Changes were on average responsive to venous interventions using lower body negative pressure, Bracelets, Valsalva and Mueller manoeuvres, and contralateral IJV compression. In comparison with terrestrial standards, spaceflight V-US did not meet all appropriateness criteria. In DVT studies (n = 3), a single thrombosis was reported and only ultrasound modality criterion met the standards. In the other studies (n = 15), all the criteria were appropriate except crew experience criterion, which was appropriate in only four studies. Future practice and research should account for microgravity-related changes, evaluate individual effect of venous interventions, and adopt Earth-based V-US standards. [ABSTRACT FROM AUTHOR]

Introduction: In 2022, the European Space Agency (ESA) held the first astronaut selection since the beginning of space flight that allowed physically impaired astronaut candidates to be selected in an inclusive European astronaut corp. The main objective of the 'parastronaut feasibility project' is to investigate if physical performance tests (PPTs) should be part of future astronaut recruitments for an inclusive ESA astronaut corps to test their flight readiness. The objectives of this study are (1) to assess if future (para-)astronaut recruitment campaigns should include PPTs to ensure flight readiness, safety, and mission success; (2) if so, which areas of physical performance should be tested to mimic nominal and off-nominal crew activities during all phases of a space mission; and (3) to assess whether PPTs are compatible with the ethical principles of equal opportunity for an inclusive pool of astronaut candidates. Methods: 58 subject matter experts with specialisations in space physiology, operational human space flight, space medicine, medical ethics or parasports were interviewed in two rounds using the Delphi method. Both qualitative and quantitative data were obtained, analysed, categorised, and visualised using the qualitative research tool NVivo and Excel. Results: Two thirds of the experts were in favour of adding PPTs to future astronaut selections and recommended to implement them for both physically unimpaired and physically impaired astronaut candidates. The main physical skills that should be examined are space-related, mission-specific coordination skills of the upper extremities, followed by endurance performance and stamina, dexterity of the upper extremities, motor learning ability and mobility. Conclusion: Based on this study, it is clear that PPTs should be part of future astronaut selection campaigns. However, the content of these PPTs must be carefully evaluated and validated using existing data on crew activities before, during, and after space flight, while considering equal opportunities in the context of human space flight. Historical considerations have influenced current astronaut requirements, but this study's findings indicate a need to reassess these requirements for future inclusive selection campaigns, as their validity and necessity remain uncertain. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Systematic review of the use of ultrasound for venous assessment and venous thrombosis screening in spaceflight" published in NPJ Microgravity. The correction states that there was an error in Table 6 of the original article, and the correct version can be found in the attached PDF file. The authors of the article are listed as Antoine Elias, Tobias Weber, David A. Green, Katie M. Harris, Jonathan M. Laws, Danielle K. Greaves, David S. Kim, Lucia Mazzolai-Duchosal, Lara Roberts, Lonnie G. Petersen, Ulrich Limper, Andrej Bergauer, Michael Elias, Andrew Winnard, and Nandu Goswami. [Extracted from the article]

A systematic review was performed to evaluate the effectiveness of nutrition as a standalone countermeasure to ameliorate the physiological adaptations of the musculoskeletal and cardiopulmonary systems associated with prolonged exposure to microgravity. A search strategy was developed to find all astronaut or human space flight bed rest simulation studies that compared individual nutritional countermeasures with non-intervention control groups. This systematic review followed the guidelines of the Cochrane Handbook for Systematic Reviews and tools created by the Aerospace Medicine Systematic Review Group for data extraction, quality assessment of studies and effect size. To ensure adequate reporting this systematic review followed the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analyses. A structured search was performed to screen for relevant articles. The initial search yielded 4031 studies of which 10 studies were eligible for final inclusion. Overall, the effect of nutritional countermeasure interventions on the investigated outcomes revealed that only one outcome was in favor of the intervention group, whereas six outcomes were in favor of the control group, and 43 outcomes showed no meaningful effect of nutritional countermeasure interventions at all. The main findings of this study were: (1) the heterogeneity of reported outcomes across studies, (2) the inconsistency of the methodology of the included studies (3) an absence of meaningful effects of standalone nutritional countermeasure interventions on musculoskeletal and cardiovascular outcomes, with a tendency towards detrimental effects on specific muscle outcomes associated with power in the lower extremities. This systematic review highlights the limited amount of studies investigating the effect of nutrition as a standalone countermeasure on operationally relevant outcome parameters. Therefore, based on the data available from the included studies in this systematic review, it cannot be expected that nutrition alone will be effective in maintaining musculoskeletal and cardiopulmonary integrity during space flight and bed rest. [ABSTRACT FROM AUTHOR]

Exercise in space has evolved from rudimental testing into the multi-modal countermeasure (CM) program used on the International Space Station (ISS). However, with the constraints of future exploration missions, replicating this program will be a significant challenge. Recent ISS data suggest that crew now experience only relatively moderate levels of microgravity (μG)-induced adaptation, although significant variation remains, with some crew displaying marked changes despite significant time/effort investment. This suggests that the efficacy of exercise CMs is yet to be optimized for all individuals. With the current suite of exercise devices operational for almost a decade, and with exploration approaching, it is timely to re-visit the terrestrial literature to identify new knowledge relevant to the management of μG adaptation. As such, the aim of the Frontiers Research Topic Optimization of Exercise Countermeasures for Human Space Flight – Lessons from Terrestrial Physiology and Operational Considerations , is to synthesize current terrestrial exercise physiology knowledge and consider how this might be employed to optimize the use of exercise CM. The purpose of this Perspective, which serves as a preface to the Research Topic is threefold: to briefly review the use and apparent efficacy of exercise in space, to consider the impact of the transition from ISS to exploration mission vehicles and habitats, and to identify areas of terrestrial exercise physiology where current knowledge might contribute to the optimization of CM exercise for exploration. These areas include individual variation, high intensity interval training, strength development/maintenance, concurrent training, plyometric/impact exercise, and strategies to enhance exercise efficacy. [ABSTRACT FROM AUTHOR]

Introduction Exposure to microgravity has various effects on the human musculoskeletal system. During spaceflight many astronauts experience low back pain and the risk of spine injuries is significantly greater post-flight. Nonetheless, the increased lumbo-pelvic injury risk is not specifically addressed by current countermeasures. Considering this, a novel exercise device has been developed to specifically counteract atrophy of deep spinal and postural muscles. The aim of the present study was to test the possibility of transferring this exercise concept from earth to space using a biomechanical simulation. Methods A biomechanical model of the exercise device was developed and validated using intramuscular electromyographic (EMG) data as previously acquired on a terrestrial prototype of the exercise device. The model was then modified to the needs of a 0- g environment, creating gravity-like conditions using shoulder straps. Results Modelled activation patterns of the investigated muscles were in line with the experimental data, showing a constant activation during exercise. The microgravity modifications of the model lead to increased muscle activation of deep spinal muscles and to decreased activation of superficial moment creating trunk muscles. Discussion The results of the biomechanical model suggest that the exercise concept can be transferred from 1- g to space conditions. The present study is a first step in the investigation process of a novel exercise concept and human studies should be conducted to confirm the present theoretical investigation. [ABSTRACT FROM AUTHOR]