Decreases in maximal oxygen uptake following long-duration spaceflight: Role of convective and diffusive O2 transport mechanisms

2017 ◽  
Vol 122 (4) ◽  
pp. 968-975 ◽  
Author(s):  
C. J. Ade ◽  
R. M. Broxterman ◽  
A. D. Moore ◽  
T. J. Barstow
Keyword(s):  
Oxygen Uptake ◽  
International Space Station ◽  
Maximal Oxygen Uptake ◽  
Linear Regression Analysis ◽  
Space Station ◽  
Hemoglobin Concentration ◽  
Integrative Approach ◽  
Transport Pathway ◽  
International Space ◽  
Long Duration

We have previously predicted that the decrease in maximal oxygen uptake (V̇o2max) that accompanies time in microgravity reflects decrements in both convective and diffusive O2 transport to the mitochondria of the contracting myocytes. The aim of this investigation was therefore to quantify the relative changes in convective O2 transport (Q̇o2) and O2 diffusing capacity (Do2) following long-duration spaceflight. In nine astronauts, resting hemoglobin concentration ([Hb]), V̇o2max, maximal cardiac output (Q̇Tmax), and differences in arterial and venous O2 contents ([Formula: see text]-[Formula: see text]) were obtained retrospectively for International Space Station Increments 19–33 (April 2009–November 2012). Q̇o2 and Do2 were calculated from these variables via integration of Fick’s Principle of Mass Conservation and Fick’s Law of Diffusion. V̇o2max significantly decreased from pre- to postflight (−53.9 ± 45.5%, P = 0.008). The significant decrease in Q̇Tmax (−7.8 ± 9.1%, P = 0.05), despite an unchanged [Hb], resulted in a significantly decreased Q̇o2 (−11.4 ± 10.5%, P = 0.02). Do2 significantly decreased from pre- to postflight by −27.5 ± 24.5% ( P = 0.04), as did the peak [Formula: see text]-[Formula: see text] (−9.2 ± 7.5%, P = 0.007). With the use of linear regression analysis, changes in V̇o2max were significantly correlated with changes in Do2 ( R2 = 0.47; P = 0.04). These data suggest that spaceflight decreases both convective and diffusive O2 transport. These results have practical implications for future long-duration space missions and highlight the need to resolve the specific mechanisms underlying these spaceflight-induced changes along the O2 transport pathway. NEW & NOTEWORTHY Long-duration spaceflight elicited a significant decrease in maximal oxygen uptake. Given the adverse physiological adaptations to microgravity along the O2 transport pathway that have been reported, an integrative approach to the determinants of postflight maximal oxygen uptake is needed. We demonstrate that both convective and diffusive oxygen transport are decreased following ~6 mo International Space Station missions.

scholarly journals Challenges for a Sustainable Food Production System on Board of the International Space Station: A Technical Review

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 687
Author(s):  
Petronia Carillo ◽  
Biagio Morrone ◽  
Giovanna Marta Fusco ◽  
Stefania De Pascale ◽  
Youssef Rouphael
Keyword(s):  
International Space Station ◽  
Life Support ◽  
Space Station ◽  
Space Missions ◽  
Sustainable Food ◽  
International Space ◽  
Physical Constraints ◽  
Fresh Food ◽  
Long Duration ◽  
Lighting Systems

The possibility of prolonging space missions—and consequently the permanence of humans in space—depends on the possibility of providing them with an adequate supply of fresh foods to meet their nutritional requirements. This would allow space travelers to mitigate health risks associated with exposure to space radiation, microgravity and psychological stress. In this review, we attempt to critically summarize existing studies with the aim of suggesting possible solutions to overcome the challenges to develop a bio-regenerative life support system (BLSS) that can contribute to life support, supplying food and O2, while removing CO2 on the International Space Station (ISS). We describe the physical constraints and energy requirements for ISS farming in relation to space and energy resources, the problems related to lighting systems and criteria for selecting plants suitable for farming in space and microgravity. Clearly, the dimensions of a growth hardware that can be placed on ISS do not allow to produce enough fresh food to supplement the stored, packaged diet of astronauts; however, experimentation on ISS is pivotal for implementing plant growth systems and paves the way for the next long-duration space missions, including those in cis-lunar space and to the lunar surface.

Long-read sequencing reveals increased occurrence of genomic variants and adenosine methylation in Bacillus pumilus SAFR-032 after long-duration flight exposure onboard the International Space Station

2021 ◽  
pp. 1-10
Author(s):  
Samantha M. Waters ◽  
S. Marshall Ledford ◽  
Amanda Wacker ◽  
Sonali Verma ◽  
Bianca Serda ◽  
...  
Keyword(s):  
International Space Station ◽  
Bacillus Pumilus ◽  
Space Station ◽  
Methylation Pattern ◽  
Low Earth Orbit ◽  
Survival Fraction ◽  
International Space ◽  
Genomic Variants ◽  
Long Duration ◽  
Long Read

Abstract Bacillus pumilus SAFR-032, an endospore-forming bacterial strain, was investigated to determine its methylation pattern (methylome) change, compared to ground control, after direct exposure to space conditions onboard the International Space Station (ISS) for 1.5 years. The resulting ISS-flown and non-flown strains were sequenced using the Nanopore MinION and an in-house method and pipeline to identify methylated positions in the genome. Our analysis indicated genomic variants and m6A methylation increased in the ISS-flown SAFR-032. To complement the broader omics investigation and explore phenotypic changes, ISS-flown and non-flown strains were compared in a series of laboratory-based chamber experiments using an X-ray irradiation source (doses applied at 250, 500, 750, 1000 and 1250 Gy); results show a potentially higher survival fraction of ISS-flown DS2 at the two highest exposures. Taken together, results from this study document lasting changes to the genome by methylation, potentially triggered by conditions in spaceflight, with functional consequences for the resistance of bacteria to stressors expected on long-duration missions beyond low Earth orbit.

American and Japanese Control-Display Stereotypes: Possible Implications for Design of Space Station Systems

1988 ◽  
Vol 32 (2) ◽  
pp. 30-34 ◽  
Author(s):  
Clifford K. Wong ◽  
John Lyman
Keyword(s):  
United States ◽  
International Space Station ◽  
Space Station ◽  
International Space ◽  
Stimulus Response ◽  
Long Duration ◽  
Weak Stimulus ◽  
Strong Control ◽  
Display Systems ◽  
Japanese Subjects

This study examined the stimulus-response stereotypes of American (United States citizens) and Japanese (Japanese citizens) subjects on the issue of control-display arrangements. Three questions were investigated. First, do Japanese and Americans operators adhere to the same compatibility principles, e.g., clockwise-for-increase, for certain configurations? Second, do the operators show similar or different responses to certain configurations? Third, are there arrangements in which both populations show strong or weak stimulus-response stereotypes? A paper and pencil test that contained 24 different control-display configurations was administered to 58 American subjects and 58 Japanese subjects, all of whom were right-handed. Out of the 24 configurations, only one elicited similar and statistically significant response stereotypes from American and Japanese subjects. The arrangement that did so emphasized that three compatibility principles (clockwise-for-increase, nearness of control-cursor relation, and scale-side) be in agreement with each other. The results provide initial, albeit speculative, guidelines for the design of control-display systems in NASA's international space station. Since multicultural crews will inhabit the space station for long duration missions, control-display designs which elicit common, consistent, and extremely strong control-movement stereotypes from different cultural populations is a necessity.

scholarly journals Salivary antimicrobial proteins and stress biomarkers are elevated during a 6-month mission to the International Space Station

2020 ◽  
Vol 128 (2) ◽  
pp. 264-275 ◽  
Author(s):  
Nadia H. Agha ◽  
Forrest L. Baker ◽  
Hawley E. Kunz ◽  
Guillaume Spielmann ◽  
Preteesh L. Mylabathula ◽  
...  
Keyword(s):  
International Space Station ◽  
Space Station ◽  
Immune Defense ◽  
Innate Immune ◽  
Viral Reactivation ◽  
Antimicrobial Proteins ◽  
First Line ◽  
International Space ◽  
Long Duration ◽  
Salivary Antimicrobial Proteins

As the international space community plans for manned missions to Mars, spaceflight-associated immune dysregulation has been identified as a potential risk to the health and safety of the flight crew. There is a need to determine whether salivary antimicrobial proteins, which act as a first line of innate immune defense against multiple pathogens, are altered in response to long-duration (>6 mo) missions. We collected 7 consecutive days of whole and sublingual saliva samples from eight International Space Station (ISS) crewmembers and seven ground-based control subjects at nine mission time points, ~180 and ~60 days before launch (L−180/L−60), on orbit at flight days ~10 and ~90 (FD10/FD90) and ~1 day before return (R−1), and at R+0, R+18, R+33, and R+66 days after returning to Earth. We found that salivary secretory (s)IgA, lysozyme, LL-37, and the cortisol-to-dehydroepiandrosterone ratio were elevated in the ISS crew before (L−180) and during (FD10/FD90) the mission. “Rookie” crewmembers embarking on their first spaceflight mission had lower levels of salivary sIgA but increased levels of α-amylase, lysozyme, and LL-37 during and after the mission compared with the “veteran” crew who had previously flown. Latent herpesvirus reactivation was distinct to the ~6-mo mission crewmembers who performed extravehicular activity (“spacewalks”). Crewmembers who shed at least one latent virus had higher cortisol levels than those who did not shed. We conclude that long-duration spaceflight alters the concentration and/or secretion of several antimicrobial proteins in saliva, some of which are related to crewmember flight experience, biomarkers of stress, and latent viral reactivation. NEW & NOTEWORTHY Spaceflight-associated immune dysregulation may jeopardize future exploration-class missions. Salivary antimicrobial proteins act as a first line of innate immune defense. We report here that several of these proteins are elevated in astronauts during an International Space Station mission, particularly in those embarking on their first space voyage. Astronauts who shed a latent herpesvirus also had higher concentrations of salivary cortisol compared with those who did not shed. Stress-relieving countermeasures are needed to preserve immunity and prevent viral reactivation during prolonged voyages into deep space.

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