Stroud M A, Ritz P, Coward W A, Sawyer M B, Constantin-Teodosiu D, Greenhaff P L, Macdonald I A
MA Stroud, Institute of Human Nutrition, Southampton General Hospital, UK.
Eur J Appl Physiol Occup Physiol. 1997;76(3):243-52. doi: 10.1007/s004210050243.
Two men, R.F. and M.S., pulled sledges each with starting masses of 222 kg, 2300 km across Antarctica. Exercise was performed for approximately 10 h each day for 95 days. Despite an average energy intake of 21.3 MJ.day-1 both subjects lost more than 25% of body weight. Energy expenditure was measured using energy balance data (EB) and isotope-labelled water (2H218O). Isotope doses were taken on day 0 and day 50 of the expedition. During the first 50 days both methods gave reasonable agreement, giving energy expenditures of 38.3 (EB) and 35.5 (2H218O) MJ.day-1 in R.F. and 28.6 (EB) and 29.1 (2H218O) MJ.day-1 in M.S. The isotope data for days 20-30 yielded exceptional values of 44.6 MJ.day-1 in R.F. and 48.7 MJ.day-1 in M.S. Estimates of energy expenditure between day 51 and day 96 were much lower and although the methods were in agreement for R.F.-24.1 (EB) and 23.1 (2H218O) MJ. day-1, there was poor agreement for MS-26.8 (EB) and 18.8 (2H218O) MJ.day-1. However, some practical difficulties occurred during this second period and there were also problems arising from marked increases in body water that made estimates of body mass and composition change difficult to interpret. The latter problems were probably due to malnutrition, which may have also been responsible for surprising increases in urinary excretion of 2H and 18O observed in both men at around day 81. These increases may reflect the release of label incorporated into molecules other than water which do not normally freely exchange with the body water pool under the circumstances of marked malnourishment. Following the expedition, both men showed declines in maximal O2 consumption (VO2max, 53.6 to 41.2 ml O2 kg-1.min-1 in R.F., 58.1-46.0 ml O2 kg-1.min-1 in M.S.); maximal voluntary isometric force production in different muscle groups (up to 19.9% in R.F. and 55.8% in M.S.) and both cytoplasmic and mitochondrial skeletal muscle enzyme activities (up to 56% in R.F. and 63% in M.S.). Plasma samples taken during the expedition showed low glucose levels, inappropriately high insulin levels, and declines in testosterone and luteinizing hormone. Thyroxine, cholesterol, albumin and triglyceride levels remained normal.
两名男子，R.F.和M.S.，各自拖着起始质量为222千克的雪橇，穿越南极洲2300千米。他们每天进行约10小时的运动，持续了95天。尽管平均能量摄入量为21.3兆焦/天，但两名受试者的体重均减轻了超过25%。能量消耗通过能量平衡数据（EB）和同位素标记水（2H218O）进行测量。在探险的第0天和第50天采集了同位素剂量。在前50天里，两种方法得出的结果较为一致，R.F.的能量消耗分别为38.3（EB）和35.5（2H218O）兆焦/天，M.S.的能量消耗分别为28.6（EB）和29.1（2H218O）兆焦/天。第20 - 30天的同位素数据显示，R.F.的能量消耗异常高，为44.6兆焦/天，M.S.为48.7兆焦/天。第51天至第96天的能量消耗估计值则低得多，虽然两种方法对R.F.的结果一致——24.1（EB）和23.1（2H218O）兆焦/天，但对M.S.的结果一致性较差——26.8（EB）和18.8（2H218O）兆焦/天。然而，在第二个阶段出现了一些实际困难，同时由于身体水分显著增加也产生了一些问题，使得体重和成分变化的估计难以解释。后一个问题可能是由于营养不良，这也可能是在大约第81天时两名男子尿液中2H和18O排泄量惊人增加的原因。这些增加可能反映了在严重营养不良情况下，标记物从结合于非水的分子中释放出来，而这些分子通常不会与身体水池自由交换。探险结束后，两名男子的最大摄氧量（VO2max）均下降（R.F.从53.6降至41.2毫升氧气/千克·分钟，M.S.从58.1降至46.0毫升氧气/千克·分钟）；不同肌肉群的最大自主等长力产生能力下降（R.F.下降高达19.9%，M.S.下降高达55.8%），细胞质和线粒体骨骼肌酶活性也下降（R.F.下降高达56%，M.S.下降高达63%）。探险期间采集的血浆样本显示葡萄糖水平低、胰岛素水平异常高，睾酮和促黄体生成素水平下降。甲状腺素、胆固醇、白蛋白和甘油三酯水平保持正常。
