Energy and water metabolism, body composition, and hormonal changes induced by 42 days of enforced inactivity and simulated weightlessness
Energy and water metabolism, body composition, and hormonal changes induced by 42 days of enforced inactivity and simulated weightlessness
复制标题
DOI：
10.1210/jc.83.12.4289
复制
发表时间：
1998-12-01
影响因子：
5.8
通讯作者：
Gauquelin-Koch, G
中科院分区：
文献类型：
--
作者：
Blanc, S;Normand, S;Gauquelin-Koch, G
不活动会导致深刻的有害变化。我们对 8 名健康男性进行了 42 天低头卧床休息 (HDBR) 对能量和水代谢的影响及其与身体成分 (BC) 以及分解代谢和合成代谢激素的相互关系的研究。 HDBR 前 15 天和最后 15 天通过双标记水法评估总能量消耗 (TEE)、体内总水分、水周转率和代谢水形成。静息能量消耗通过间接量热法测定，BC通过双能X射线吸收法测定。每天测量皮质醇、GH、去甲变肾上腺素、变肾上腺素、尿素和肌酐的尿排泄量。 HDBR 导致体重 (2%)、体内总水分 (5%)、代谢水 (17%) 和去脂体重 (LBM; 4%) 显着减少，但脂肪量和水分周转率没有变化。节段BC显示腿部和躯干的LBM减少，而脂肪量增加，但手臂没有明显变化。 LBM 的水合作用没有改变。 TEE 和能量摄入显着下降（20% 和 13%），而静息能量消耗则保持不变。体力活动支出下降了 39%。受试者在 HDBR 期间处于能量平衡状态，而在对照期间为负能量平衡（-1.5 MJ/天）。尿去甲肾上腺素（23%）和变肾上腺素（23%）下降，但尿皮质醇（28%；第2和3周）、GH（75%；第2-4周）和尿素（15%；第3和第4周）增加。结论是，在延长的 HDBR 过程中，水代谢没有发生相关变化。 BC 变化发生在未运动的身体部位，TEE 的减少是由于不活动，而不是 LBM 损失。此外，体重本身并不能准确反映受试者的能量状态，并且能量平衡本身无法解释体重减轻，体重减轻涉及短暂的代谢应激。
Inactivity causes profound deleterious changes. We investigated in eight healthy men the impact of a 42-day head-down bed rest (HDBR) on energy and water metabolism and their interrelationships with body composition (BC) and catabolic and anabolic hormones. Total energy expenditure (TEE), total body water, water turnover, and metabolic water formation were assessed by the doubly labeled water method 15 days before and for the last 15 days of HDBR. Resting energy expenditure was determined by indirect calorimetry, and BC was determined by dual energy x-ray absorptiometry. Urinary excretion of cortisol, GH, normetanephrine, metanephrine, urea, and creatinine were measured daily. HDBR resulted in significant reductions in body weight (2%), total body water (5%), metabolic water (17%), and lean body mass (LBM; 4%), but fat mass and water turnover did not change. Segmental BC showed a decreased LBM in legs and trunk, whereas fat mass increased, no significant changes were noted in the arms. The hydration of LBM was unchanged. TEE and energy intake decreased significantly (20% and 13%), whereas resting energy expenditure was maintained. Expenditure for physical activity dropped by 39%. Subjects were in energy balance during HDBR, whereas it was negative during the control period (-1.5 MJ/day). There were decreases in urinary normetanephrine (23%) and metanephrine (23%), but urinary cortisol (28%; weeks 2 and 3), GH (75%; weeks 2-4), and urea (15%; weeks 3 and 4) increased. It was concluded that during prolonged HDBR no relevant modifications in water metabolism were triggered. BC changes occurred in the nonexercised body segments, and the reduction in TEE was due to inactivity, not to LBM loss. Moreover, body weight alone does not accurately reflect the subject's energy state, and energy balance alone could not explain the body weight loss, which involves a transient metabolic stress.