title: Exercise load index and changes in body weight during long-duration confinement in an isolated environment.
abstract: OBJECTIVE
  The objectives of this project were to investigate exercise load and body weight related to long-duration confinement in a closed environment simulating ISS flight conditions, and to evaluate subjects' motivation to continue the experiment and their adaptation to isolation.
  
  
  METHODS
  Four Russian male subjects participated in a 240-d experiment (Group I), and four subjects (three male subjects and one female subject) from Austria, Canada, Japan, and Russia participated in a 110-d experiment (Group II). Exercise load was estimated during confinement using a modified Rating of Perceived Exertion scale. Free reports were used to determine subjects' motivation. Body weight was measured before, during, and after confinement.
  
  
  RESULTS
  Group I achieved their lowest exercise loads during their first month of isolation; problems with adaptation to the isolation environment were also reported during this first month. Group II exercise load was significantly lower in the second month due to crewmember problems; loss of motivation could be noted from their free reports. The subject with the lowest exercise load retired from the isolation experiment earlier than scheduled. Exercise load was not correlated with prior exercise habits. Significant differences in body weight was observed between group I and II and between Russian and non-Russian subjects. One subject in Group I experienced a significant increase in his body weight.
  
  
  CONCLUSIONS
  Exercise load may be a good indicator for adaptation problems and motivation changes in closed environments. Immobility, lack of space, and smoking cessation in general did not induce significant body weight changes.
authors.affiliation: Human Factors Research and Technology, NASA Ames Research Center, Moffett Field,CA 94035-1000, USA. nkraft@mail.arc.nasa.gov
authors.forename: Norbert O
authors.initials: NO
authors.lastname: Kraft
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Lyons
authors.forename: Heidi
authors.initials: H
authors.lastname: Binder
authors.forename: Natsuhiko
authors.initials: N
authors.lastname: Inoue
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohshima
authors.forename: Chiharu
authors.initials: C
authors.lastname: Sekiguchi
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D001835:Body Weight; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007103:Immobilization; D008297:Male; D008875:Middle Aged; D009042:Motivation; D016540:Smoking Cessation; D013026:Space Flight; D018561:Space Simulation; D013997:Time Factors