高原低氧对青少年最大氧供给和氧利用的影响

Characteristics and Correlative Factors of Maximal Oxygen Supply and Consumption in Teenager Residents at Various Altitudes

目的:探讨高原低氧对青少年最大氧耗量(VO2max)、最大氧供给量(DO2max)及氧利用的影响。方法:对三个不同海拔高度(2 260m,3 417m,4 300m)各15例健康青少年的氧动力学指标进行测试。用自行车负荷递增法直接测VO2max等气体交换指标;耳氧仪同步记录氧饱和度(SO2);心阻抗法测定最大心指数(CImax)。结果:血红蛋白浓度(Hb)随海拔高度的升高而增大(P<0.05);VO2max、DO2max、CImax和SO2均随海拔升高而下降(P<0.05);三个海拔高度的最大氧摄取率(ERO2)无明显变化;VO2max和DO2max在三个海拔高度及总体样本中均呈显著直线相关(r=0.77、0.71、0.72、0.98,P<0.05)。结论:随海拔高度的升高VO2max、DO2max逐渐下降。高原青少年VO2max降低的原因为DO2max不足,而非氧利用障碍;CImax和SO2的下降是DO2max不足的决定因素,同时也是VO2max降低的主要原因。

Objective： To study the characteristics and correlative factors of maximal oxygen supply and consumption in teenager residents at various altitudes. Methods： The oxygen kinetics of 15 resident teenagers at 3 altitude levels was investigated. Hb concentration, maximal oxygen up-take （VO2max）, maximal oxygen supply （DO2max）, oxygen saturation （SO2） and maximal cardiac output per square meter of body surface （Cimax） were measured during maximal exercise. Results： Hb concentration in residents at higher altitudes （3 417m,4 300m） was higher than that in residents at lower altitude （P 〈0.05, while VO2max, DO2max, CImax and SO2 in residents at higher altitude were lower than those in residents of lower altitude （ P 〈 0.05, VO2max was linearly correlated with DO2max in all subjects at various altitudes （ r = 0.77,0. 71,0.72,0.98, P 〈 0.05. Conclusions： It was sug- gested that the level of VO2max and DO2max were decreased with the increased altitude. The decreased VO2max in teenagers was result of DO2max adequate at higher altitude but not oxygen utilization, and the lowering of CImax and S02 were the main factors of DO2.