title: An exercise protocol designed to control energy expenditure for long-term space missions.
abstract: BACKGROUND
  Astronauts experience weight loss during spaceflight. Future space missions require a more efficient exercise program not only to maintain work efficiency, but also to control increased energy expenditure (EE). When discussing issues concerning EE incurred through exercise, excess post-exercise energy expenditure (EPEE) must also be considered. The aim of this study was to compare the total EE, including EPEE, induced by two types of interval cycling protocols with the total EE of a traditional, continuous cycling protocol.
  
  
  METHODS
  There were 10 healthy men, ages 20 to 31 yr, who completed 3 exercise sessions: sprint interval training (SIT) consisting of 7 sets of 30-s cycling at 120% VO2max with a 15-s rest between each bout; high-intensity interval aerobic training (HIAT) consisting of 3 sets of 3-min cycling at 80-90% VO2max with a 2-min active rest at 50% VO2max; and continuous aerobic training (CAT) consisting of 40 min of cycling at 60-65% VO2max. During each session, resting metabolic rate, exercise EE, and a 180-min post-exercise EE were measured.
  
  
  RESULTS
  The EPEEs during the SIT, HIAT, and CAT averaged 32 +/- 19, 21 +/- 16, and 13 +/- 13 kcal, and the total EE for an entire exercise/ rest session averaged 109 +/- 20, 182 +/- 17, and 363 +/- 45 kcal, respectively. While the EPEE after the CAT was significantly less than after the SIT, the total EE with the CAT was the greatest of the three.
  
  
  CONCLUSIONS
  The SIT and HIAT would be potential protocols to control energy expenditure for long space missions.
authors.affiliation: Japan Aerospace Exploration Agency, Tsukuba, Ibaraki, Japan. matsuo.tomoaki@jaxa.jp
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Matsuo
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ohkawara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Seino
authors.forename: Nobutake
authors.initials: N
authors.lastname: Shimojo
authors.forename: Shin
authors.initials: S
authors.lastname: Yamada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohshima
authors.forename: Kiyoji
authors.initials: K
authors.lastname: Tanaka
authors.forename: Chiaki
authors.initials: C
authors.lastname: Mukai
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D018480:Astronauts; D002153:Calorimetry, Indirect; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015431:Weight Loss / Q000502:physiology; D055815:Young Adult