Conkin J, Powell M R
Life Sciences Research Laboratories, NASA-Johnson Space Center, Houston, TX, USA.
Aviat Space Environ Med. 2001 Mar;72(3):202-14.
We define lower body adynamia (LBA) as restricted lower body movement, particularly walking, during both the denitrogenation phase at site pressure and during the exercise phase while at altitude.
Our null hypothesis is that subjects who are adynamic in the lower body but do upper body exercise will be at similar risk of decompression sickness (DCS) and venous gas emboli (VGE) as subjects who randomly walk but do no planned exercise while at altitude.
We selected a data set that contained 1401 altitude exposures with the following conditions: a) walking was part of the exercise at altitude; or b) there was no planned exercise done at altitude but walking was not restricted; or c) LBA was inforced, but upper body exercise was done at altitude. We used logistic regression (LR) on all 1401 exposures, a log logistic survival analysis (SA) on a subset of data from "a" and "c" (n = 234), and estimated a model for how the incidence of VGE changes through time.
The estimated probabilities of DCS and VGE with 95% confidence intervals (Cls) from the LR with a simulation of a 3-h oxygen prebreathe, a 4-h exposure to 4.3 psia in a male, and exercise and LBA conditions as described above are: (see text).
LBA that includes upper body exercise appears to be as protective against DCS and VGE as random walking by subjects who did no prescribed exercise while at altitude, and is more protective than exercise that included walking. Our conclusions are based on an assumption that we have adequately controlled, through our data selection process and the use of multivariable models, important variables in tests that were not done at the Johnson Space Center.
我们将下身运动不能（LBA）定义为在地面压力下的去氮阶段以及在高海拔运动阶段期间下身运动受限，尤其是行走受限。
我们的零假设是，下身运动不能但进行上身运动的受试者发生减压病（DCS）和静脉气体栓塞（VGE）的风险与在高海拔随机行走但未进行有计划运动的受试者相似。
我们选择了一个包含1401次高海拔暴露情况的数据集，条件如下：a）行走是高海拔运动的一部分；或b）在高海拔未进行有计划运动，但行走不受限；或c）强制出现LBA，但在高海拔进行了上身运动。我们对所有1401次暴露情况使用逻辑回归（LR），对来自“a”和“c”子集的数据（n = 234）进行对数逻辑生存分析（SA），并估计了VGE发病率随时间变化的模型。
通过模拟3小时氧气预呼吸、男性在4.3 psia下暴露4小时以及上述运动和LBA条件，从LR得出的DCS和VGE的估计概率及95%置信区间（Cls）如下：（见正文）。
包括上身运动的LBA似乎与在高海拔未进行规定运动的受试者随机行走一样，对DCS和VGE具有保护作用，并且比包括行走的运动更具保护作用。我们的结论基于这样一个假设，即我们通过数据选择过程和多变量模型的使用，充分控制了在约翰逊航天中心未进行的测试中的重要变量。
