Effects of exercises performed in the work environment on occupational stress: A systematic review.

INTRODUCTION: Technological advances stimulate labor transformations in such a way that the search for productivity, goals and market competitiveness leads industries and companies to neglect the health and safety of their workers. There is a gap in the literature regarding means of intervention using physical exercises (PE), with details remaining unknown in terms of appropriate exercise prescriptions or types that minimize the effects of occupational stress. OBJECTIVE: to verify the effects on workers' stress of PE performed in the work environment. METHOD: this systematic review searched for randomized controlled trials (RCTs) in 08 databases (MEDLINE, Cochrane, BIREME, LILACS, EBSCOhost, SCOPUS, Web of Science and Embase), in English and Portuguese, published between 2017 and 2021. The PICOS strategy was used to determine inclusion, being P: male and female workers; I: exercises performed in the work environment; C: control group without intervention; O: occupational stress; and S: controlled experiments. Methodological quality, risk of bias and reliability of assessments were analyzed using the TESTEX, Risk of Bias 2, and Kappa scales. RESULTS: A total of 07 articles were included, of which, most had good methodological quality and unclear risk of bias. The intra- and inter-rater reliability test of methodological quality showed excellent agreement. As a limitation, the fragility in allocation concealment, blinding and absence of treatment analysis was noted in the studies evaluated. CONCLUSION: PE in the workplace might have positive effects on reducing occupational stress, but further studies must be conducted to better clarify this. This review was registered with PROSPERO (CRD42022304106).

Pathophysiology, risk, diagnosis, and management of venous thrombosis in space: where are we now?

The recent incidental discovery of an asymptomatic venous thrombosis (VT) in the internal jugular vein of an astronaut on the International Space Station prompted a necessary, immediate response from the space medicine community. The European Space Agency formed a topical team to review the pathophysiology, risk and clinical presentation of venous thrombosis and the evaluation of its prevention, diagnosis, mitigation, and management strategies in spaceflight. In this article, we discuss the findings of the ESA VT Topical Team over its 2-year term, report the key gaps as we see them in the above areas which are hindering understanding VT in space. We provide research recommendations in a stepwise manner that build upon existing resources, and highlight the initial steps required to enable further evaluation of this newly identified pertinent medical risk.

Effects of a microgravity SkinSuit on lumbar geometry and kinematics.

PURPOSE: Astronauts returning from long ISS missions have demonstrated an increased incidence of lumbar disc herniation accompanied by biomechanical and morphological changes associated with spine elongation. This research describes a ground-based study of the effects of an axial compression countermeasure Mk VI SkinSuit designed to reload the spine and reduce these changes before return to terrestrial gravity. METHODS: Twenty healthy male volunteers aged 21-36 without back pain participated. Each lay overnight on a Hyper Buoyancy Flotation (HBF) bed for 12 h on two occasions 6 weeks apart. On the second occasion participants donned a Mk VI SkinSuit designed to axially load the spine at 0.2 Gz during the last 4 h of flotation. Immediately after each exposure, participants received recumbent MRI and flexion-extension quantitative fluoroscopy scans of their lumbar spines, measuring differences between spine geometry and intervertebral kinematics with and without the SkinSuit. This was followed by the same procedure whilst weight bearing. Paired comparisons were performed for all measurements. RESULTS: Following Mk VI SkinSuit use, participants evidenced more flexion RoM at L3-4 (p = 0.01) and L4-5 (p = 0.003), more translation at L3-4 (p = 0.02), lower dynamic disc height at L5-S1 (p = 0.002), lower lumbar spine length (p = 0.01) and greater lordosis (p = 0.0001) than without the Mk VI SkinSuit. Disc cross-sectional area and volume were not significantly affected. CONCLUSION: The MkVI SkinSuit restores lumbar mobility and lordosis following 4 h of wearing during hyper buoyancy flotation in a healthy control population and may be an effective countermeasure for post space flight lumbar disc herniation.

Development of a Digital Platform: A Perspective to Advance Space Telepharmacy.

Goal: Lessons learned from decades of human spaceflight have helped advance the delivery of healthcare in rural and remote areas of the globe. Inclusion of the public in spaceflights is not yet accompanied by technology capable of monitoring their physical and mental health, managing clinical conditions, and rapidly identifying medical emergencies. Telepharmacy is a practice prioritizing pharmacotherapeutic guidance and monitoring to help improve patient quality of life, and can potentially expand the field of space medicine. We seek to advance pharmaceutical care through telepharmacy by developing a digital platform. Objective: This study focuses on the development of a digital platform for teleassistance and pharmaceutical teleconsulting services that builds on lessons learned in delivering space medicine. Methods: The platform contains evidence-based information on various drugs grouped by medical specialty, and also records and saves patient appointments. It has specific service protocols for service standardization, including artificial intelligence, to allow agility in services and escalation. All data is protected by privacy and professional ethics guidelines. Results: The telepharmacy platform is ready and currently undergoing testing for ground applications through validation studies in hospitals or medical clinics. Conclusions: Although developed for use on Earth, this telepharmacy platform provides a good example of how terrestrial healthcare knowledge and technology can be transferred to space missions.

Effectiveness of CPR in Hypogravity Conditions-A Systematic Review.

(1) Background: Cardiopulmonary resuscitation (CPR), as a form of basic life support, is critical for maintaining cardiac and cerebral perfusion during cardiac arrest, a medical condition with high expected mortality. Current guidelines emphasize the importance of rapid recognition and prompt initiation of high-quality CPR, including appropriate cardiac compression depth and rate. As space agencies plan missions to the Moon or even to explore Mars, the duration of missions will increase and with it the chance of life-threatening conditions requiring CPR. The objective of this review was to examine the effectiveness and feasibility of chest compressions as part of CPR following current terrestrial guidelines under hypogravity conditions such as those encountered on planetary or lunar surfaces; (2) Methods: A systematic literature search was conducted by two independent reviewers (PubMed, Cochrane Register of Controlled Trials, ResearchGate, National Aeronautics and Space Administration (NASA)). Only controlled trials conducting CPR following guidelines from 2010 and after with advised compression depths of 50 mm and above were included; (3) Results: Four different publications were identified. All studies examined CPR feasibility in 0.38 G simulating the gravitational force on Mars. Two studies also simulated hypogravity on the Moon with a force of 0.17 G/0,16 G. All CPR protocols consisted of chest compressions only without ventilation. A compression rate above 100/s could be maintained in all studies and hypogravity conditions. Two studies showed a significant reduction of compression depth in 0.38 G (-7.2 mm/-8.71 mm) and 0.17 G (-12.6 mm/-9.85 mm), respectively, with nearly similar heart rates, compared to 1 G conditions. In the other two studies, participants with higher body weight could maintain a nearly adequate mean depth while effort measured by heart rate (+23/+13.85 bpm) and VO2max (+5.4 mL·kg-1·min-1) increased significantly; (4) Conclusions: Adequate CPR quality in hypogravity can only be achieved under increased physical stress to compensate for functional weight loss. Without this extra effort, the depth of compression quickly falls below the guideline level, especially for light-weight rescuers. This means faster fatigue during resuscitation and the need for more frequent changes of the resuscitator than advised in terrestrial guidelines. Alternative techniques in the straddling position should be further investigated in hypogravity.

Air Traffic Controllers and Executive Brain Function.

BACKGROUND: This study evaluated the executive functions of air traffic controllers (ATCs) in relation to demographic and occupational characteristics such as length of service, technical qualifications, and work shifts.METHODS: This was a cross-sectional study based on a convenience sample with sequential selection of 52 Brazilian ATCs using the Wisconsin Card Sorting Test (WCST), questionnaire applied to the ATCs, Student's t-test, and one-way analysis of variance with post hoc Tukey multiple comparisons of WCST with functional characteristics.RESULTS: ATCs with 0 to 5 yr of service presented scores significantly above the cohort average in the WCST [0-5 yr: 0.54 ± 0.01 vs. 6-15 yr: 0.31 ± 0.52 vs. 151 yr: -0.02 ± 0.80]. ATCs working a 3-shift pattern presented an efficient performance and fewer perseverative errors in the WCST (3-shift: -0.63 ± 0.38 vs. 4-shift: -0.45 ± 0.43), that did not rise to significance. In a comparison between executive brain functions and technical qualifications, the controllers who worked in the TWR (Aerodrome Control Tower) only, and those who worked in both the TWR and APP (Approach Control Service) showed no differences in the number of completed categories and in perseverative errors.DISCUSSION:The executive brain functioning of the ATCs, such as mental flexibility, strategic planning and inhibitory control, were identified as being above average when compared to the general population. While alterations in work shifts appear to have a negative (but nonsignificant) impact, newer ATCs showed stronger scores than more experienced ATCs on the WCST. Successful performance as an ATC has complex foundations, such as understanding the context of air navigation and having strong executive function capabilities.de Freitas AM, Portuguez MW, Russomano, T, da Costa JC. Air traffic controllers and executive brain function. Aerosp Med Hum Perform. 2022; 93(5):426-432.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations.

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

Effective recommendations towards healthy routines to preserve mental health during the COVID-19 pandemic

Objective: To assess the adherence to a set of evidence-based recommendations to support mental health during the coronavirus disease 2019 (COVID-19) pandemic and its association with depressive and anxiety symptoms. Methods: A team of health workers and researchers prepared the recommendations, formatted into three volumes (1: COVID-19 prevention; 2: Healthy habits; 3: Biological clock and sleep). Participants were randomized to receive only Volume 1 (control), Volumes 1 and 2, Volumes 1 and 3, or all volumes. We used a convenience sample of Portuguese-speaking participants over age 18 years. An online survey consisting of sociodemographic and behavioral questionnaires and mental health instruments (Patient Health Questionnaire-9 [PHQ-9] and Generalized Anxiety Disorder-7 [GAD-7]) was administered. At 14 and 28 days later, participants were invited to complete follow-up surveys, which also included questions regarding adherence to the recommendations. A total of 409 participants completed the study - mostly young adult women holding university degrees. Results: The set of recommendations contained in Volumes 2 and 3 was effective in protecting mental health, as suggested by significant associations of adherence with PHQ-9 and GAD-7 scores (reflecting anxiety and depression symptoms, respectively). Conclusion: The recommendations developed in this study could be useful to prevent negative mental health effects in the context of the pandemic and beyond.

Effective recommendations towards healthy routines to preserve mental health during the COVID-19 pandemic.

OBJECTIVE: To assess the adherence to a set of evidence-based recommendations to support mental health during the coronavirus disease 2019 (COVID-19) pandemic and its association with depressive and anxiety symptoms. METHODS: A team of health workers and researchers prepared the recommendations, formatted into three volumes (1: COVID-19 prevention; 2: Healthy habits; 3: Biological clock and sleep). Participants were randomized to receive only Volume 1 (control), Volumes 1 and 2, Volumes 1 and 3, or all volumes. We used a convenience sample of Portuguese-speaking participants over age 18 years. An online survey consisting of sociodemographic and behavioral questionnaires and mental health instruments (Patient Health Questionnaire-9 [PHQ-9] and Generalized Anxiety Disorder-7 [GAD-7]) was administered. At 14 and 28 days later, participants were invited to complete follow-up surveys, which also included questions regarding adherence to the recommendations. A total of 409 participants completed the study - mostly young adult women holding university degrees. RESULTS: The set of recommendations contained in Volumes 2 and 3 was effective in protecting mental health, as suggested by significant associations of adherence with PHQ-9 and GAD-7 scores (reflecting anxiety and depression symptoms, respectively). CONCLUSION: The recommendations developed in this study could be useful to prevent negative mental health effects in the context of the pandemic and beyond.

Randomized Comparison of Two New Methods for Chest Compressions during CPR in Microgravity-A Manikin Study.

BACKGROUND: Although there have been no reported cardiac arrests in space to date, the risk of severe medical events occurring during long-duration spaceflights is a major concern. These critical events can endanger both the crew as well as the mission and include cardiac arrest, which would require cardiopulmonary resuscitation (CPR). Thus far, five methods to perform CPR in microgravity have been proposed. However, each method seems insufficient to some extent and not applicable at all locations in a spacecraft. The aim of the present study is to describe and gather data for two new CPR methods in microgravity. MATERIALS AND METHODS: A randomized, controlled trial (RCT) compared two new methods for CPR in a free-floating underwater setting. Paramedics performed chest compressions on a manikin (Ambu Man, Ambu, Germany) using two new methods for a free-floating position in a parallel-group design. The first method (Schmitz-Hinkelbein method) is similar to conventional CPR on earth, with the patient in a supine position lying on the operator's knees for stabilization. The second method (Cologne method) is similar to the first, but chest compressions are conducted with one elbow while the other hand stabilizes the head. The main outcome parameters included the total number of chest compressions (n) during 1 min of CPR (compression rate), the rate of correct chest compressions (%), and no-flow time (s). The study was registered on clinicaltrials.gov (NCT04354883). RESULTS: Fifteen volunteers (age 31.0 ± 8.8 years, height 180.3 ± 7.5 cm, and weight 84.1 ± 13.2 kg) participated in this study. Compared to the Cologne method, the Schmitz-Hinkelbein method showed superiority in compression rates (100.5 ± 14.4 compressions/min), correct compression depth (65 ± 23%), and overall high rates of correct thoracic release after compression (66% high, 20% moderate, and 13% low). The Cologne method showed correct depth rates (28 ± 27%) but was associated with a lower mean compression rate (73.9 ± 25.5/min) and with lower rates of correct thoracic release (20% high, 7% moderate, and 73% low). CONCLUSIONS: Both methods are feasible without any equipment and could enable immediate CPR during cardiac arrest in microgravity, even in a single-helper scenario. The Schmitz-Hinkelbein method appears superior and could allow the delivery of high-quality CPR immediately after cardiac arrest with sufficient quality.

Human Health during Space Travel: State-of-the-Art Review.

The field of human space travel is in the midst of a dramatic revolution. Upcoming missions are looking to push the boundaries of space travel, with plans to travel for longer distances and durations than ever before. Both the National Aeronautics and Space Administration (NASA) and several commercial space companies (e.g., Blue Origin, SpaceX, Virgin Galactic) have already started the process of preparing for long-distance, long-duration space exploration and currently plan to explore inner solar planets (e.g., Mars) by the 2030s. With the emergence of space tourism, space travel has materialized as a potential new, exciting frontier of business, hospitality, medicine, and technology in the coming years. However, current evidence regarding human health in space is very limited, particularly pertaining to short-term and long-term space travel. This review synthesizes developments across the continuum of space health including prior studies and unpublished data from NASA related to each individual organ system, and medical screening prior to space travel. We categorized the extraterrestrial environment into exogenous (e.g., space radiation and microgravity) and endogenous processes (e.g., alteration of humans' natural circadian rhythm and mental health due to confinement, isolation, immobilization, and lack of social interaction) and their various effects on human health. The aim of this review is to explore the potential health challenges associated with space travel and how they may be overcome in order to enable new paradigms for space health, as well as the use of emerging Artificial Intelligence based (AI) technology to propel future space health research.

Using supraglottic airways by paramedics for airway management in analogue microgravity increases speed and success of ventilation.

In the next few years, the number of long-term space missions will significantly increase. Providing safe concepts for emergencies including airway management will be a highly challenging task. The aim of the present trial is to compare different airway management devices in simulated microgravity using a free-floating underwater scenario. Five different devices for airway management [laryngeal mask (LM), laryngeal tube (LT), I-GEL, direct laryngoscopy (DL), and video laryngoscopy (VL)] were compared by n = 20 paramedics holding a diving certificate in a randomized cross-over setting both under free-floating conditions in a submerged setting (pool, microgravity) and on ground (normogravity). The primary endpoint was the successful placement of the airway device. The secondary endpoints were the number of attempts and the time to ventilation. A total of 20 paramedics (3 female, 17 male) participated in this study. Success rate was highest for LM and LT and was 100% both during simulated microgravity and normogravity followed by the I-GEL (90% during microgravity and 95% during normogravity). However, the success rate was less for both DL (60% vs. 95%) and VL (20% vs. 60%). Fastest ventilation was performed with the LT both in normogravity (13.7 ± 5.3 s; n = 20) and microgravity (19.5 ± 6.1 s; n = 20). For the comparison of normogravity and microgravity, time to ventilation was shorter for all devices on the ground (normogravity) as compared underwater (microgravity). In the present study, airway management with supraglottic airways and laryngoscopy was shown to be feasible. Concerning the success rate and time to ventilation, the optimum were supraglottic airways (LT, LM, I-GEL) as their placement was faster and associated with a higher success rate. For future space missions, the use of supraglottic airways for airway management seems to be more promising as compared to tracheal intubation by DL or VL.

Cardiopulmonary Resuscitation in Hypogravity Simulation.

BACKGROUND: Limited research exists into extraterrestrial CPR, despite the drive for interplanetary travel. This study investigated whether the terrestrial CPR method can provide quality external chest compressions (ECCs) in line with the 2015 UK resuscitation guidelines during ground-based hypogravity simulation. It also explored whether gender, weight, and fatigue influence CPR quality.METHODS: There were 21 subjects who performed continuous ECCs for 5 min during ground-based hypogravity simulations of Mars (0.38 G) and the Moon (0.16 G), with Earths gravity (1 G) as the control. Subjects were unloaded using a body suspension device (BSD). ECC depth and rate, heart rate (HR), ventilation (VE), oxygen uptake (Vo2), and Borg scores were measured.RESULTS: ECC depth was lower in 0.38 G (42.9 9 mm) and 0.16 G (40.8 9 mm) compared to 1 G and did not meet current resuscitation guidelines. ECC rate was adequate in all gravity conditions. There were no differences in ECC depth and rate when comparing gender or weight. ECC depth trend showed a decrease by min 5 in 0.38 G and by min 2 in 0.16 G. Increases in HR, VE, and Vo2 were observed from CPR min 1 to min 5.DISCUSSION: The terrestrial method of CPR provides a consistent ECC rate but does not provide adequate ECC depths in simulated hypogravities. The results suggest that a mixed-gender space crew of varying bodyweights may not influence ECC quality. Extraterrestrial-specific CPR guidelines are warranted. With a move to increasing ECC rate, permitting lower ECC depths and substituting rescuers after 1 min in lunar gravity and 4 min in Martian gravity is recommended.Sriharan S, Kay G, Lee JCY, Pollock RD, Russomano T. Cardiopulmonary resuscitation in hypogravity simulation. Aerosp Med Hum Perform. 2021; 92(2):106112.

Cardiopulmonary resuscitation (CPR) during spaceflight - a guideline for CPR in microgravity from the German Society of Aerospace Medicine (DGLRM) and the European Society of Aerospace Medicine Space Medicine Group (ESAM-SMG).

BACKGROUND: With the "Artemis"-mission mankind will return to the Moon by 2024. Prolonged periods in space will not only present physical and psychological challenges to the astronauts, but also pose risks concerning the medical treatment capabilities of the crew. So far, no guideline exists for the treatment of severe medical emergencies in microgravity. We, as a international group of researchers related to the field of aerospace medicine and critical care, took on the challenge and developed a an evidence-based guideline for the arguably most severe medical emergency - cardiac arrest. METHODS: After the creation of said international group, PICO questions regarding the topic cardiopulmonary resuscitation in microgravity were developed to guide the systematic literature research. Afterwards a precise search strategy was compiled which was then applied to "MEDLINE". Four thousand one hundred sixty-five findings were retrieved and consecutively screened by at least 2 reviewers. This led to 88 original publications that were acquired in full-text version and then critically appraised using the GRADE methodology. Those studies formed to basis for the guideline recommendations that were designed by at least 2 experts on the given field. Afterwards those recommendations were subject to a consensus finding process according to the DELPHI-methodology. RESULTS: We recommend a differentiated approach to CPR in microgravity with a division into basic life support (BLS) and advanced life support (ALS) similar to the Earth-based guidelines. In immediate BLS, the chest compression method of choice is the Evetts-Russomano method (ER), whereas in an ALS scenario, with the patient being restrained on the Crew Medical Restraint System, the handstand method (HS) should be applied. Airway management should only be performed if at least two rescuers are present and the patient has been restrained. A supraglottic airway device should be used for airway management where crew members untrained in tracheal intubation (TI) are involved. DISCUSSION: CPR in microgravity is feasible and should be applied according to the Earth-based guidelines of the AHA/ERC in relation to fundamental statements, like urgent recognition and action, focus on high-quality chest compressions, compression depth and compression-ventilation ratio. However, the special circumstances presented by microgravity and spaceflight must be considered concerning central points such as rescuer position and methods for the performance of chest compressions, airway management and defibrillation.

Space motion sickness: A common neurovestibular dysfunction in microgravity.

This article presents a review of the current findings related to neurovestibular physiology, aetiology, and proposed theories on space motion sickness (SMS) during acute and sustained exposure to microgravity. The review discusses the available treatment options including medication and nonpharmacological countermeasure methods that help to prevent the development of SMS in weightlessness. Ground-based simulations using virtual reality, flight simulations, and Barany's chairs can be applied to study SMS and demonstrate its signs and symptoms to space crew members. Space motion sickness has been observed in approximately 70% of astronauts within the first 72 h in microgravity, having in general an instantaneous onset of signs and symptoms. Stomach discomfort, nausea, vomiting, pallor, cold sweating, salivation, tachypnoea, belching, fatigue, drowsiness, and stress hormone release have been documented. This can have detrimental effects on the well-being of astronauts in the initial phase of a space mission. Mental and physical performance may be affected, jeopardizing operational procedures and mission safety.

Mars walking simulation: An electromyographic analysis.

CONTEXT: With a long duration return mission to Mars on the horizon, we must learn as much about the environment and its influence on the musculoskeletal system as possible to develop countermeasures and mitigate deleterious health effects and maladaptation. AIMS: To determine the influence of simulated Mars gravity on the activity of four locomotor muscles while walking, in comparison to 1 G, using lower body positive pressure (LBPP). MATERIAL AND METHODS: A total of 14 male subjects (mean age: 20.6 ± 2.4 years) performed bouts of walking in both simulated Mars gravity (0.38 G) and Earth gravity (1 G) using an LBPP device. The dependent variables were the muscle activity evoked in the tibialis anterior, vastus lateralis, gluteus maximus and lateral portion of the gastrocnemius, measured using electromyography and expressed as percentages of maximum voluntary isometric contractions, and heart rate (HR). For statistical analysis, a paired t-test was performed. Statistical significance was defined as P < 0.05. RESULTS: No significant differences in muscle activity were found across conditions for any of the investigated muscles. A significant mean difference in the HR was identified between Earth (105.15 ± 8.1 bpm) and Mars (98.15 ± 10.44 bpm) conditions (P = 0.027), wherein the HR was lower during the Mars trial. CONCLUSIONS: The Mars environment may not result in any deteriorative implications for the musculoskeletal system. However, if future research should report that stride frequency and thus activation frequency is decreased in the simulated Mars gravity, negative implications may be posed for muscle retention and reconditioning efforts on the Red Planet.

Neurological changes in outer space.

Space travel, once considered esoteric and part of science fiction, is becoming a reality in our lifetime. Closely monitoring health parameters in real-time and providing health care to Vyomanauts 200 km above the Earth's surface will be a reality in India, in just another 40 months. This will be the ultimate feat in Telemedicine! This review article gives an overview of what a "Space Doctor" needs to know with specific reference to the nervous system.

Acute Physical Effort Increases Sympathovagal Balance Responses to Autonomic Stimulation in Metabolic Syndrome.

BACKGROUND: There is little evidence of how metabolic syndrome (MS) affects sympathovagal balance responses to acute physical effort (APE) and autonomic stimulation (AS). This study aimed to evaluate the heart rate variability (HRV) responses to the combined APE and AS challenges. METHODS: Fourteen subjects (8 men; 49.15 ± 8.67 years) divided into two groups: 7 healthy volunteers [control group (CG)] and 7 patients with MS. Sympathovagal balance [low frequency (LF)/high frequency (HF) ratio] was accessed by HRV through the beat-to-beat heart rate (HR) electrocardiogram. Other variables analyzed were as follows: HR, RR-interval variance (VAR/ms2), LF and HF normalized units (un). The APE consisted of a 30-min walk at 65%-75% of the age-predicted maximal HR. The AS was achieved by changing from the supine to standing position (activity orthostatic position). RESULTS: At rest, all HRV variables differ with on MS, but after APE and AS LF (nu) and HF (nu) become similar to the CG. However, the LF/HF ratio responses to the AS were significantly different after APE, but only in the MS (CG rest: 367% ± 59% vs. recovery 495% ± 116%, P > 0.05; MS rest: 316% ± 88% vs. recovery: 665% ± 165%; P = 0.045). Comparing the difference between AS in rest and recovery (ΔAS = rest - recovery), the LF/HF ratio was notably higher in the MS group (CG: 94% ± 29% vs. MS: 415% ± 76%; P < 0.0001). CONCLUSIONS: The APE and AS induced by body posture changes activated a clear distinction in sympathovagal balance response in MS.

A new method for the performance of external chest compressions during hypogravity simulation.

INTRODUCTION: 2015 UK resuscitation guidelines aim for 50-60 mm depth when giving external chest compressions (ECCs). This is achievable in hypogravity if the rescuer flexes and extends their arms during CPR, or using a new method trialed; the 'Mackaill-Russomano' (MR CPR) method. METHODS: 10 participants performed 3 sets of 30 ECCs in accordance with 2015 guidelines. A control was used at 1Gz, with eight further conditions using Mars and Moon simulations, with and without braces in the terrestrial position and using the MR CPR method. The MR CPR method involved straddling the mannequin, using its legs for stabilization. A body suspension device, with counterweights, simulated hypogravity environments. ECC depth, rate, angle of arm flexion and heart rate (HR) were measured. RESULTS: Participants completed all conditions, and ECC rate was achieved throughout. Mean (±â€¯SD) ECC depth using the MR CPR method at 0.38Gz was 54.1 ±â€¯0.55 mm with braces; 50.5 ±â€¯1.7 mm without. ECCs were below 50 mm at 0.17Gz using the MR CPR method (47.5 ±â€¯1.47 mm with braces; 47.4 ±â€¯0.87 mm without). In the terrestrial position, ECCs were more effective without braces (49.4 ±â€¯0.26 mm at 0.38Gz; 43.9 ±â€¯0.87 mm at 0.17Gz) than with braces (48.5 ±â€¯0.28 mm at 0.38Gz; 42.4 ±â€¯0.3 mm at 0.17Gz). Flexion increased from approximately 2° - 8° with and without braces respectively. HR did not change significantly from control. DISCUSSION: 2015 guidelines were achieved using the MR CPR method at 0.38Gz, with no significant difference with and without braces. Participants were closer to achieving the required ECC depth in the terrestrial position without braces. ECC depth was not achieved at 0.17Gz, due to a greater reduction in effective body weight.