Comparison of ground-based and space flight energy expenditure and water turnover in middle-aged healthy male US astronauts

• Published in: The American journal of clinical nutrition Vol. 65; no. 1; pp. 4 - 12
• Main Authors: Lane, HW, Gretebeck, RJ, Schoeller, DA, Davis-Street, J, Socki, RA, Gibson, EK
• Format: Journal Article
• Language: English
• Published: Legacy CDMS Elsevier Inc 01.01.1997; American Society for Clinical Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: Adult; Aging - metabolism; Aging - physiology; Applied physiology; Astronauts; Biological and medical sciences; Body Mass Index; Body Weight - physiology; Deuterium; Eating - physiology; Energy Metabolism - physiology; Gravitation; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Life Sciences (General); Male; Males; Medical sciences; Metabolism; Methods; Middle Aged; NASA Center JSC; NASA Discipline Regulatory Physiology; Nutrition; Oxygen Isotopes; Space Flight; Transports. Aerospace. Diving. Altitude; Water - metabolism; Weightlessness; World Health Organization; NASA Center JSC; NASA Discipline Regulatory Physiology; Deuterium; Comparative Study; Middle Aged; Eating/physiology; Male; Short Duration; Oxygen Isotopes; Water/metabolism; Adult; Energy Metabolism/physiology; Support, U.s. Gov't, Non-P.h.s; Body Mass Index; Human; Body Weight/physiology; Gravitation; World Health Organization; Aging/metabolism/physiology; Weightlessness; Space Flight; Sts Shuttle Project; Flight Experiment; Nasa Center Jsc; Nasa Discipline Regulatory Physiology; Astronauts; Manned; Methods; Crew; Energy metabolism; Middle age; Astronaut; Energy requirement; Environmental factor; Water balance; Space flight; Comparative study; Feeding
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/65.1.4

Energy requirements during space flight are poorly defined because they depend on metabolic-balance studies, food disappearance, and dietary records. Water turnover has been estimated by balance methods only. The purpose of this study was to determine energy requirements and water turnover for short-term space flights (8–14 d). Subjects were 13 male astronauts aged 36–51 y with normal body mass indexes (BMIs). Total energy expenditure (TEE) was determined during both a ground-based period and space flight and compared with the World Health Organization (WHO) calculations of energy requirements and dietary intake. TEE was not different for the ground-based and the space-flight periods (12.40 +/- 2.83 and 11.70 +/- 1.89 MJ/d, respectively), and the WHO calculation using the moderate activity correction was a good predictor of TEE during space flight. During the ground-based period, energy intake and TEE did not differ, but during space flight energy intake was significantly lower than TEE; body weight was also less at landing than before flight. Water turnover was lower during space flight than during the ground-based period (2.7 +/- 0.6 compared with 3.8 +/- 0.5 L/d), probably because of lower fluid intakes and perspiration loss during flight. This study confirmed that the WHO calculation can be used for male crew members' energy requirements during short space flights.