不同海拔高度青少年最大氧供给和氧利用的特点及影响因素

目的探讨高原青少年最大氧耗量（ＶＯ２ｍａｘ）、最大氧供给量（ＤＯ２ｍａｘ）及氧利用的特点。方法对三个不同海拔高度（２２６０ｍ，３４１７ｍ，４３００ｍ）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定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。

Characteristics and affecting factors of maximal oxygen supply and consumption in teenager residents at various altitudes

bjective To study the characteristics and affecting factors of maximal oxygen supply and consumption in teenager residents at various altitudes. Methods The oxygen kinetics of 15 resident teenagers of 3 altitude levels were investigated.Hb concentration,maximal oxygen uptake( O2max),maximal oxygen supply(DO2max),oxygen saturation(SO2),maximal cardiac output per square meter of body surface(CImax)were measured during maximal exercise. Results Hb concentration in residents of higher altitudes (3 417 m,4 300 m) was higher than that in residents of lower altitude(P<0.05), while O2max,DO2max,CImax and SO2 in residents of higher altitude were lower than those in residents of lower altitude(P<0.05), O2max was linearly correlated with DO2max in all subjects of various altitudes(r=0.770.710.720.98,P<0.05). Conclusions It was suggested that the lowered O2max in higher altitude teenagers was the result of in adequate AKV5O2max,but not oxygen malutilization,and the lowering of CImax and SO2 were the determinant factors of DO2.