Planetary Habitat Simulation: Nutrition Studies

A loss of body weight has been documented in lowland-living individuals when exposed to hypoxic environments, such as at high altitude, or under laboratory conditions. A reduction in appetite and energy intake has also been reported during conditions of microgravity, such as during space flight. Fourteen normal or over-weight men, who are otherwise healthy, will undergo 3x 21-day interventions; normobaric normoxic bed rest (NBR; FiO2=21%), normobaric hypoxic ambulatory confinement (HAMB; FiO2=14%; \~4000 m simulated altitude), and normobaric hypoxic bed rest (HBR; FiO2=14%). The effects of hypoxia and bedrest on appetite and its hormonal control will be assessed before and at day 17 of each intervention using a mixed meal tolerance test.