title: Metabolic energy required for flight.
abstract: This paper reviews data available from U.S. and U.S.S.R. studies on energy metabolism in the microgravity of space flight.  Energy utilization and energy availability in space seem to be similar to those on Earth.  However, negative nitrogen balances in space in the presence of adequate energy and protein intakes and in-flight exercise, suggest that lean body mass decreases in space.  Metabolic studies during simulated (bed rest) and actual microgravity have shown changes in blood glucose, fatty acids, and insulin levels, suggesting that energy metabolism may be altered during flight.  Future research should focus on the interactions of lean body mass, diet, and exercise in space and their roles in energy metabolism during space flight.
authors.affiliation: Biomedical Operations and Research Branch, NASA Johnson Space Center, Houston, TX 77058, USA.
authors.forename: H W
authors.initials: HW
authors.lastname: Lane
authors.forename: R J
authors.initials: RJ
authors.lastname: Gretebeck
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001481:Basal Metabolism / Q000502:physiology*; D001510:Bed Rest; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition / Q000502:physiology; D004040:Dietary Carbohydrates / Q000378:metabolism; D004044:Dietary Proteins / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology; D018478:Extravehicular Activity / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism / Q000652:urine; D013026:Space Flight; D014893:Weightlessness
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D009584:Nitrogen