Loeppky J A, Sheard A C, Salgado R M, Mermier C M
1 Research Section: VA Medical Center , Albuquerque, NM, USA (retired) and Adjunct Faculty: Department of Health, Exercise and Sports Sciences, The University of New Mexico , Albuquerque, NM, USA.
2 School of Kinesiology and Nutritional Science, California State University , Los Angeles, CA, USA.
Physiol Int. 2016 Sep;103(3):377-391. doi: 10.1556/2060.103.2016.3.1.
This study compared the ventilation response to an incremental ergometer exercise at two altitudes: 633 mmHg (resident altitude = 1,600 m) and following acute decompression to 455 mmHg (≈4,350 m altitude) in eight male cyclists and runners. At 455 mmHg, the VSTPD at RER <1.0 was significantly lower and the VBTPS was higher because of higher breathing frequency; at VOmax, both VSTPD and VBTPS were not significantly different. As percent of VOmax, the VBTPS was nearly identical and VSTPD was 30% lower throughout the exercise at 455 mmHg. The lower VSTPD at lower pressure differs from two classical studies of acclimatized subjects (Silver Hut and OEII), where VSTPD at submaximal workloads was maintained or increased above that at sea level. The lower VSTPD at 455 mmHg in unacclimatized subjects at submaximal workloads results from acute respiratory alkalosis due to the initial fall in HbO (≈0.17 pHa units), reduction in PACO (≈5 mmHg) and higher PAO throughout the exercise, which are partially pre-established during acclimatization. Regression equations from these studies predict VSTPD from VO and P in unacclimatized and acclimatized subjects. The attainment of ventilatory acclimatization to altitude can be estimated from the measured vs. predicted difference in VSTPD at low workloads after arrival at altitude.
本研究比较了8名男性自行车运动员和跑步运动员在两个海拔高度下对递增式测力计运动的通气反应：633 mmHg（居住海拔 = 1600米）以及急性减压至455 mmHg（≈海拔4350米）后。在455 mmHg时，呼吸交换率（RER）<1.0时的标准体温、压力、干燥气体容积（VSTPD）显著降低，而体温、压力、饱和水蒸气容积（VBTPS）因呼吸频率较高而升高；在最大摄氧量（VOmax）时，VSTPD和VBTPS均无显著差异。以VOmax的百分比计算，在455 mmHg的整个运动过程中，VBTPS几乎相同，而VSTPD低30%。较低压力下较低的VSTPD与两项针对适应环境受试者的经典研究（银屋研究和OEII研究）不同，在这两项研究中，次最大工作量时的VSTPD维持不变或高于海平面时的水平。未适应环境的受试者在次最大工作量时455 mmHg下较低的VSTPD是由于血红蛋白氧（HbO）最初下降（≈0.17个动脉血pH单位）、动脉血二氧化碳分压（PACO）降低（≈5 mmHg）以及整个运动过程中肺泡氧分压（PAO）较高导致的急性呼吸性碱中毒，这些在适应过程中部分已经预先形成。这些研究的回归方程可预测未适应环境和适应环境受试者的VSTPD与摄氧量（VO）和压力（P）的关系。到达海拔高度后，可根据低工作量时测量的与预测的VSTPD差异来估计对海拔高度的通气适应程度。
