Exercise in space: the European Space Agency approach to in-flight exercise countermeasures for long-duration missions on ISS.

Volker Damann,Joachim Mester,Andre Rosenberger,Tobias Weber,Gunda Lambrecht,Nora Petersen,Inessa Kozlovskaya,Patrick Jaekel,Lori Ploutz-Snyder,Filippo Castrucci,Jonathan Scott

doi:10.1186/s13728-016-0050-4

Abstract

BackgroundTo counteract microgravity (µG)-induced adaptation, European Space Agency (ESA) astronauts on long-duration missions (LDMs) to the International Space Station (ISS) perform a daily physical exercise countermeasure program. Since the first ESA crewmember completed an LDM in 2006, the ESA countermeasure program has strived to provide efficient protection against decreases in body mass, muscle strength, bone mass, and aerobic capacity within the operational constraints of the ISS environment and the changing availability of on-board exercise devices. The purpose of this paper is to provide a description of ESA’s individualised approach to in-flight exercise countermeasures and an up-to-date picture of how exercise is used to counteract physiological changes resulting from µG-induced adaptation. Changes in the absolute workload for resistive exercise, treadmill running and cycle ergometry throughout ESA’s eight LDMs are also presented, and aspects of pre-flight physical preparation and post-flight reconditioning outlined.ResultsWith the introduction of the advanced resistive exercise device (ARED) in 2009, the relative contribution of resistance exercise to total in-flight exercise increased (33–46 %), whilst treadmill running (42–33 %) and cycle ergometry (26–20 %) decreased. All eight ESA crewmembers increased their in-flight absolute workload during their LDMs for resistance exercise and treadmill running (running speed and vertical loading through the harness), while cycle ergometer workload was unchanged across missions.ConclusionIncreased or unchanged absolute exercise workloads in-flight would appear contradictory to typical post-flight reductions in muscle mass and strength, and cardiovascular capacity following LDMs. However, increased absolute in-flight workloads are not directly linked to changes in exercise capacity as they likely also reflect the planned, conservative loading early in the mission to allow adaption to µG exercise, including personal comfort issues with novel exercise hardware (e.g. the treadmill harness). Inconsistency in hardware and individualised support concepts across time limit the comparability of results from different crewmembers, and questions regarding the difference between cycling and running in µG versus identical exercise here on Earth, and other factors that might influence in-flight exercise performance, still require further investigation.

Highlights

To counteract microgravity-induced adaptation, European Space Agency (ESA) astronauts on long-duration missions (LDMs) to the International Space Station (ISS) perform a daily physical exercise counter‐ measure program
The purpose of this paper is, threefold: first, it is to provide a description of the ESA Space Medicine Office’s individualised approach to the delivery of exercise support to ESA crewmembers, the provision of in-flight exercise countermeasures during LDMs; second, it is to provide the reader with an up-to-date picture of the human spaceflight on the ISS and how exercise is used to counteract physiological changes resulting from adaptation to prolonged exposure to μG; and it is hoped that it will serve as a reference document for scientists planning and implementing experiments on ISS in which ESA crewmembers serve as volunteers, to aid them in both interpreting their data and designing future experimental protocols that are compatible with ESA medical operations requirements
The total number of sessions completed on all ISS exercise devices by the eight LDM ESA crewmembers was 1785

Summary

Introduction

To counteract microgravity (μG)-induced adaptation, European Space Agency (ESA) astronauts on long-duration missions (LDMs) to the International Space Station (ISS) perform a daily physical exercise counter‐ measure program. The increase in astronaut numbers and the length of missions, and the resulting rapid increase in the total number of man-days in space—over 2000 per year on ISS—have revealed the profound multi-system changes that take place in the human body as it adapts to μG This adaptation, frequently referred to as de-conditioning, because the changes that occur are unfavourable for life in Earth’s gravitational environment, is associated with reductions in bone mass, muscle volume and strength, and cardiovascular capacity, and changes to blood pressure regulation and vestibular and sensorimotor function [1,2,3,4,5,6,7], while publically, the effects of LDMs are characterised by post-flight images of markedly weakened crewmembers struggling to walk and occasionally fainting.

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