A Method of Ground Simulation of Physiological Effects of Hypogravity on Humans

Baranov, M. V.; Katuntsev, V. P.; Шпаков, А. В.; Baranov, V. M.

doi:10.1007/s10517-016-3181-0

Cited by 22 publications

(9 citation statements)

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“…The final 43 included studies were mainly case series studies except for the case report of Waligora and Horrigan ( 1975 ) and the study of Baranov et al ( 2016 ) who conducted a randomized controlled trial. Apart from the two latter publications, all other included studies investigated different levels of partial gravity without a separated control group.…”

Section: Resultsmentioning

confidence: 99%

“…The main findings of this study were the heterogeneity of results across studies, the extremely large effect sizes within a wide range of effect sizes, the low quality of applied methodologies as well as the discovery of a significant lack of knowledge concerning long-term adaptations in partial gravity. The longest continuous exposure to partial gravity reported in one of the included studies was a period of 2 weeks, with 9.6° head-up tilt during daytime and 0° supine position during the nights (Baranov et al, 2016 ). The reasons for the heterogeneous findings across studies can be explained as follows: (1) The included studies reported a wide range of ages; (2) Studies were performed with both male and female participants.…”

Section: Discussionmentioning

confidence: 99%

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Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

et al. 2017

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The European Space Agency has recently announced to progress from low Earth orbit missions on the International Space Station to other mission scenarios such as exploration of the Moon or Mars. Therefore, the Moon is considered to be the next likely target for European human space explorations. Compared to microgravity (μg), only very little is known about the physiological effects of exposure to partial gravity (μg < partial gravity <1 g). However, previous research studies and experiences made during the Apollo missions comprise a valuable source of information that should be taken into account when planning human space explorations to reduced gravity environments. This systematic review summarizes the different effects of partial gravity (0.1–0.4 g) on the human musculoskeletal, cardiovascular and respiratory systems using data collected during the Apollo missions as well as outcomes from terrestrial models of reduced gravity with either 1 g or microgravity as a control. The evidence-based findings seek to facilitate decision making concerning the best medical and exercise support to maintain astronauts' health during future missions in partial gravity. The initial search generated 1,323 publication hits. Out of these 1,323 publications, 43 studies were included into the present analysis and relevant data were extracted. None of the 43 included studies investigated long-term effects. Studies investigating the immediate effects of partial gravity exposure reveal that cardiopulmonary parameters such as heart rate, oxygen consumption, metabolic rate, and cost of transport are reduced compared to 1 g, whereas stroke volume seems to increase with decreasing gravity levels. Biomechanical studies reveal that ground reaction forces, mechanical work, stance phase duration, stride frequency, duty factor and preferred walk-to-run transition speed are reduced compared to 1 g. Partial gravity exposure below 0.4 g seems to be insufficient to maintain musculoskeletal and cardiopulmonary properties in the long-term. To compensate for the anticipated lack of mechanical and metabolic stimuli some form of exercise countermeasure appears to be necessary in order to maintain reasonable astronauts' health, and thus ensure both sufficient work performance and mission safety.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

et al. 2017

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“…Thus, astronauts spending extended periods of time in lunar (0.16-G z ) and Martian (0.38-G z ) may not be at a reduced risk of SANS and IJV thrombosis when in these partial gravity environments. Recently, Baranov et al (2016) reported, there was insufficient evidence to conclude that IJV diameter measured in six subjects after a simulated 3-week lunar mission [consisting 1 week of continuous 6° head-down tilt bed rest followed by 2 weeks of bed rest in which the subjects were horizontal (0° of tilt) for 8 h during sleep and at 9.6° of head-up tilt for 16 h during the day] differed from the IJV diameter of five subjects who underwent 3 weeks of simulated weightlessness (continuous 6° head-down tilt bed rest). Thus, countermeasures that would be employed by astronauts while weightless during transit to and from their destination also may be required during stays on these extraterrestrial surfaces.…”

Section: Countermeasuresmentioning

confidence: 99%

Venous and Arterial Responses to Partial Gravity

et al. 2020

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Introduction: Chronic exposure to the weightlessness-induced cephalad fluid shift is hypothesized to be a primary contributor to the development of spaceflight-associated neuro-ocular syndrome (SANS) and may be associated with an increased risk of venous thrombosis in the jugular vein. This study characterized the relationship between gravitational level (G z-level) and acute vascular changes. Methods: Internal jugular vein (IJV) cross-sectional area, inferior vena cava (IVC) diameter, and common carotid artery (CCA) flow were measured using ultrasound in nine subjects (5F, 4M) while seated when exposed to 1.00-G z , 0.75-G z , 0.50-G z , and 0.25-G z during parabolic flight and while supine before flight (0-G analog). Additionally, IJV flow patterns were characterized. Results: IJV cross-sectional area progressively increased from 12 (95% CI: 9-16) mm 2 during 1.00-G z seated to 24 (13-35), 34 (21-46), 68 (40-97), and 103 (75-131) mm 2 during 0.75-G z , 0.50-G z , and 0.25-G z seated and 1.00-G z supine, respectively. Also, IJV flow pattern shifted from the continuous forward flow observed during 1.00-G z and 0.75-G z seated to pulsatile flow during 0.50-G z seated, 0.25-G z seated, and 1.00-G z supine. In contrast, we were unable to detect differences in IVC diameter measured during 1.00-G seated and any level of partial gravity or during 1.00-G z supine. CCA blood flow during 1.00-G seated was significantly less than 0.75-G z and 1.00-G z supine but differences were not detected at partial gravity levels 0.50-G z and 0.25-G z. Conclusions: Acute exposure to decreasing G z-levels is associated with an expansion of the IJV and flow patterns that become similar to those observed in supine subjects and in astronauts during spaceflight. These data suggest that G z-levels greater than 0.50-G z may be required to reduce the weightlessness-induced headward fluid shift that may contribute to the risks of SANS and venous thrombosis during spaceflight.

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“…For the remaining 16 days, they were switched to the head-up bed rest at plus 9.6 for 16 h a day (from 7 am to 11 pm) to be returned to the horizontal position for night (from 11 pm to 7 am). According to Baranov et al (2015), these conditions simulate the physiological effects of a man's stay at the lunar surface. All subjects stayed in an air-conditioned bedroom maintained at temperature of 25 AE 0.5 C and relative humidity of 60-70 %.…”

Section: Study Protocolmentioning

confidence: 99%

Effect of Simulated Microgravity and Lunar Gravity on Human Inspiratory Muscle Function: ‘Selena-T’ 2015 Study

Segizbaeva

Aleksandrova

Donina

et al. 2016

Pulmonary Dysfunction and Disease

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As a part of the multi-disciplinary "SELENA-T"-2015 Bed Rest Study, we investigated the pattern of inspiratory muscles fatigue in 22 healthy male subjects during incremental exercise test to exhaustion before and after 21 days of hypokinesia evoked by bed rest. Hypokinesia consisted of head-down bed rest (HDBR) at a minus 6° angle, simulating microgravity present on orbiting spacecraft, in 10 subjects. The remaining 12 subjects spent the first 5 days of hypokinesia in HDBR position and the subsequent 16 days in head-up bed rest (HUBR) at a plus 9.6° angle, as a presumed analog of lunar gravity that is six times less than Earth's gravity. Maximal inspiratory pressure (MIP) and electromyograms (EMG) of the diaphragm (D), parasternal (PS), sternocleidomastoid (SCM), and scalene (S) muscles served as indices of inspiratory muscle function. Before both HDBR and HUBR, exercise decreased MIP and centroid frequency (fc) of EMG (D, PS, SCM, and S) power spectrum (p < 0.05). After 3 weeks of HDBR, but not HUBR, inspiratory muscles fatigue was more expressed compared with control (p < 0.05). We conclude that HDBR lowers inspiratory muscles resistance to fatigue during high-intensity exercise while HUBR has no such effect. These changes may limit maximal ventilation and may contribute to exercise intolerance observed after prolonged simulated microgravity. The physiological mechanisms of respiratory muscle dysfunction after HDBR consist primarily of postural effects, and are not due only to hypokinesia.

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A Method of Ground Simulation of Physiological Effects of Hypogravity on Humans

Cited by 22 publications

References 1 publication

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

Venous and Arterial Responses to Partial Gravity

Effect of Simulated Microgravity and Lunar Gravity on Human Inspiratory Muscle Function: ‘Selena-T’ 2015 Study

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