Abstract
1835 Astronauts in space consume fewer calories and return to earth predisposed to orthostatic intolerance. The role that caloric deficit plays in the modulation of autonomic control of the cardiovascular system is unknown. PURPOSE: To determine the effects of 6° head down bedrest (an analog of spaceflight) with a hypocaloric diet (25% caloric restriction) on autonomic neural control during static handgrip (HG) and cold pressor (CP) tests. METHODS: Ten healthy young men participated in a randomized crossover bedrest (BR) study, consisting of four, twoweek interventions (hypocaloric ambulatory, hypocaloric bedrest, normocaloric ambulatory, and normocaloric bedrest), each separated by 5 months. Heart rate, arterial pressure, and muscle sympathetic nerve activity were recorded before, during, and after HG (40% of maximum voluntary contraction to fatigue), post-exercise muscle ischemia (forearm occlusion), and CP. Bedrest and nutritional combinations were compared using two-way ANOVA with repeated measures. RESULTS: Cardiovascular responses during exercise were similar in all conditions; however, the pressor response elicited by post-exercise muscle ischemia tended to be less well-preserved following bedrest regardless of nutritional status. Autonomic and hemodynamic responses to CP were not significantly different between the four interventions. CONCLUSIONS: Although bedrest may cause some attenuation of the muscle metaboreflex, exercise cardiovascular responses are well-preserved after 14 days of BR independent of caloric intake. Supported by National Space Biomedical Research Institute Contract TD00206.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
