Effect of 29 days of simulated microgravity on maximal oxygen consumption and fat-free mass of rats

摘要: To determine the time course of changes in maximal oxygen consumption (VO2max) and its relationships with body composition, a 29-d simulated microgravity study was initiated 30 adult female rats (230-280 g) randomly assigned to one three experimental groups; namely, head-down suspension (HDS) at 45 degrees, horizontal (HS) 0 degree, or cage control (CC). Five separate exercise performance tests measurements related VO2max, treadmill run time, mechanical efficiency were conducted before on days 7, 14, 21, 28. The animals sacrificed chemically analyzed for fat fat-free free mass (FFM) between 22 29. When results expressed an absolute basis (ml.min-1), both groups had significant decreases day 7. Thereafter, HDS remained significantly decreased, while HS returned values not different than presuspension by relative (ml.kg-1.min-1), all exhibited reductions 6-8%. Both suspended less CC but similar FFM (p greater 0.05). VO2max evaluated basis, group mean that 6% lower other two groups, difference statistically significant. Treadmill reduced after 28 d reduction from pre-suspension being more pronounced animals.(ABSTRACT TRUNCATED AT 250 WORDS)