Determination of Intracellular and Extracellular Fluid Volume in Humans in Space Flight (Sprut-MBI (Octopus-MBI)) - 03.19.15

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The incredible shrinking astronaut. This investigation, one of several efforts to understand hydration and blood pressure adaptation in microgravity, highlighted the importance of gravity to the body’s water-electrolyte balance. A non-invasive device developed for the study allowed repeat, real-time measurements of hydration status during space flight. All subjects showed uniform loss of body fluids during long-term flight, with maximum loss immediately after return to Earth. Decrease in body fluids and related changes in body composition cause loss of muscle mass as well.  One week post-flight, data showed signs of recovering pre-flight hydration status and body mass.

The following content was provided by V B. Noskov, and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)

  • V B. Noskov, Institute for Biomedical Problems, Moscow, Russia

  • Co-Investigator(s)/Collaborator(s)
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    Sponsoring Space Agency
    Russian Federal Space Agency (Roscosmos)

    Sponsoring Organization
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    Research Benefits
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    ISS Expedition Duration
    June 2002 - April 2006

    Expeditions Assigned

    Previous ISS Missions
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    Experiment Description

    Research Overview
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    Investigation of a state of human liquid media, assessment of adaptation mechanisms and prevention of unfavorable impact of zero-gravity on the hydration status and post-flight orthostatic tolerance.

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    Space Applications
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    Earth Applications
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    Operational Requirements
    Sprut-K Kit to determine different human liquid volumes by measuring the impedance of the body and its segments, Body mass meter with a range from 50 kg to 100 kg with an accuracy of 0.25 kg, Hematokrit microcentrifuge to separate plasma from erythrocytes, laptop and power supply unit.

    Operational Protocols
    Determination of volumes of intracellular and intercellular liquid, body's total liquid, circulating blood and relation between cellular and liquid blood component.

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    Results/More Information

    Studies performed with prolonged inactivity, or antiorthostatic hypokinesia (AOSH), on Earth and during space flights showed that gravity plays an important role in many physiological systems of the human body, including water-salt balance, and hydration. The noninvasive Sprut-MBI (Octopus-Multifrequency Bioelectrical Impedance) investigation was conducted in the course of ISS Expeditions 1-12. Twelve Russian cosmonauts took part in monitoring their hydration state using a especially developed portable SPRUT-K impedance meter. Results showed that at different stages of 100- to 200-day flights, cosmonauts’ body liquid volume was reduced: the overall, intracellular and extracellular, volumes became on average 5.2 to 10.4% less compared to baseline level. The in-flight changes in their body’s composition were also consistent: while the lean mass loss determined by impedance measurement was insignificant (on average, from 1.9 to 4.0%), the gain of the fatty mass ranged from 4.6 to 8.2% during the first three months of the flight. Thus, hydration of a human body decreased during the long-term space flight, which was accompanied by reduction of the muscular mass and the gain in fatty mass (Noskov et al. 2007, 2011). A concurrent experiment studied the state of body fluids of a cosmonaut over a ten-day ISS mission with 6 ground subjects over a seven-day AOSH. Bioimpedancemetry (electrical resistance measurement of the body) was performed before the flight and on the seventh day during the flight, as well as on the first and sixth days after landing. Intracellular and extracellular fluid volumes, body composition, and total body water (TBW) content were determined and showed water compartments in the cosmonaut’s body were decreased to the same degree as in the ground group by the seventh day of AOSH. The amount of total body fluids and intracellular and extracellular volumes were decreased by 5.6 to 6.5 % from the baseline level (a decrease of ~13% in hydration on the first day of flight was the most pronounced). Lean body mass was insignificantly decreased, whereas the adipose (fatty) component of body weight was increased by 14.5%. When results were compared, the direction and degree of changes in the hydration status and body composition in space and on the ground, under similar body fluid shift conditions, were identical. A week after the flight, all parameters studied showed a clear tendency toward recovery to their pre-flight levels. Bioimpedance results are in agreement with data obtained previously using invasive techniques and affirm the general concepts of adaptation of water–salt homeostasis to microgravity.

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    Results Publications

      Noskov VB, Nichiporuk IA, Grigoriev AI.  Dynamics of the Body Liquids and Composition in Long-duration Space Flight (Bioimpedance Analysis). Human Physiology. 2011; 37: 821-825. DOI: 10.1134/S0362119711070231.

      Noskov VB, Nichiporuk IA.  Changes in the volume of the fluid spaces in the body of a cosmonaut during long-term spaceflight. Rossiĭskii fiziologicheskiĭ zhurnal imeni I.M. Sechenova / Rossiĭskaia akademiia nauk. 2004; 90(8): 76.

      Noskov VB, Nikolayev DV, Tuykin SA, Kozharinov VI, Grachev VA.  Portable impedancementer for evaluating the body's fluid spaces during spaceflight. Meditsinskaia Tekhnika (Biomedical Engineering). 2007(2): 45-47.

      Noskov VB, Nikolaev DV, Tuikin SA, Kozharinov VI, Grachev VA.  A Portable Impedance Meter for Monitoring Liquid Compartments of the Human Body Under Space Flight Conditions. Meditsinskaia Tekhnika (Biomedical Engineering). 2007; 41(2): 94-96. DOI: 10.1007/s10527-007-0020-7.

      Noskov VB, Nichiporuk IA, Grigoriev AI.  Changes in fluid media and body composition during long-term spaceflight (bioimpedance analysis). Aviakosmicheskaia i Ekologicheskaia Meditsina (Aerospace and Environmental Medicine). 2007; 41(3): 3-7.

      Noskov VB, Kotov AN.  Impedancemetric research of hydration status and body composition during antiorthostatic . Aviakosmicheskaia i Ekologicheskaia Meditsina (Aerospace and Environmental Medicine). 2005; 39(4): 41-45.

      Noskov VB, Nichiporuk IA, Morukov BV, Malenchenko YI.  Study of the state of human bodily fluids during long-term spaceflight. Aviakosmicheskaia i Ekologicheskaia Meditsina (Aerospace and Environmental Medicine). 2005; 39(1): 27-31.

      Noskov VB, Kotov AN, Morukov BV, Nichiporuk IA, Shargin YG.  Bioimpedance Analysis of Fluids and Body Composition Under the Conditions of Short-term Space Flight or Hypokinesia. Human Physiology. 2006; 32(5): 622-625. DOI: 10.1134/S0362119706050197. [Also: V.B. Noskov, A.N. Kotov, B.V. Morukov, I.A. Nichiporuk, Yu.G. Shargin, "Bioimpedance Analysis of Fluids and Body Composition During Sort-Term Spaceflights and Hypokinesia," Fiziologiya Cheloveka, 2006, Vol. 32, No. 5, pp. 136–139.]

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    Ground Based Results Publications

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    ISS Patents

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    Related Publications

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    Related Websites
    Energia - Science Research on the ISS Russian Segment

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