Steinacker J M, Liu Y, Böning D, Halder A, Maassen N, Thomas A, Stauch M
Abt. Sport-und Leistungsmedizin, Universität Ulm, Germany.
Eur J Appl Physiol Occup Physiol. 1996;74(1-2):187-93. doi: 10.1007/BF00376512.
Studies were made of pulmonary diffusion capacity and oxygen transport before and after an expedition to altitudes at and above 4900 m. Maximum power (Pmax) and maximal oxygen uptake (VO2max) were measured in 11 mountaineers in an incremental cycle ergometer test (25W.min-1) before and after return from basecamp (30 days at 4900 m or higher). In a second test, cardiac output (Qc) and lung diffusion capacity of carbon monoxide (DL,cg) were measured by acetylene and CO rebreathing at rest and during exercise at low, medium and submaximal intensities. After acclimatization, VO2max and Pmax decreased by 5.1% [from 61.0 (SD 6.2) to 57.9 (SD 10.2) ml.kg-1, n.s.] and 9.9% [from 5.13 (SD 0.66) to 4.62 (SD 0.42) W.kg-1, n.s.], respectively. The maximal cardiac index and DL,cg decreased significantly by 15.6% [14.1 (SD 1.41) 1.min-1.m-2 to 11.9 (SD 1.44)1.min-1.m-2, P < 0.05] and 14.3% [85.9 (SD 4.36) ml.mmHg-1. min-1 to 73.6 (SD 15.2) ml.mmHg-1.min-1, P < 0.05], respectively. The expedition to high altitude led to a decrease in maximal Qc, oxygen uptake and DL,cg. A decrease in muscle mass and capillarity may have been responsible for the decrease in maximal Qc which may have resulted in a decrease of DL,cg and an increase in alveolar-arterial oxygen difference. The decrease in DL,cg especially at lower exercise intensities after the expedition may have been due to a ventilation-perfusion mismatch and changes in blood capacitance. At higher exercise intensities diffusion limitation due to reduced pulmonary capillary contact time may also have occurred.
对一支前往海拔4900米及以上地区的探险队队员在探险前后的肺扩散容量和氧运输情况进行了研究。在11名登山者从大本营返回前后（在4900米或更高海拔停留30天），通过递增式自行车测力计测试（25瓦·分钟⁻¹）测量了最大功率（Pmax）和最大摄氧量（VO₂max）。在第二项测试中，通过乙炔和一氧化碳再呼吸法，在静息状态以及低、中、次最大强度运动时测量心输出量（Qc）和一氧化碳肺扩散容量（DL,cg）。适应环境后，VO₂max和Pmax分别下降了5.1%[从61.0（标准差6.2）降至57.9（标准差10.2）毫升·千克⁻¹，无显著差异]和9.9%[从5.13（标准差0.66）降至4.62（标准差0.42）瓦·千克⁻¹，无显著差异]。最大心指数和DL,cg分别显著下降了15.6%[从14.1（标准差1.41）升·分钟⁻¹·米⁻²降至11.9（标准差1.44）升·分钟⁻¹·米⁻²，P<0.05]和14.3%[从85.9（标准差4.36）毫升·毫米汞柱⁻¹·分钟⁻¹降至73.6（标准差15.2）毫升·毫米汞柱⁻¹·分钟⁻¹，P<0.05]。前往高海拔地区的探险导致最大Qc、摄氧量和DL,cg下降。肌肉质量和毛细血管密度的降低可能是最大Qc下降的原因，这可能导致了DL,cg的下降以及肺泡-动脉氧分压差的增加。探险后DL,cg的下降，尤其是在较低运动强度时，可能是由于通气-灌注不匹配和血容量变化。在较高运动强度时，由于肺毛细血管接触时间减少，也可能出现扩散限制。
