乳酸阈强度下探讨无氧阈机制的人体与动物实验研究

Experimental Study on Mechanism of Anaerobic Threshold

目的:分别通过人体和动物实验探讨乳酸阈强度下代谢转变的机制。方法:选取24名体育专业学生作为人体组,进行递增负荷功率自行车运动;选取30只SD大鼠作为大鼠组,进行递增负荷游泳运动。首先确定两组受试各自的乳酸阈强度,后在不吸氧与补充吸氧条件下按相同运动方案进行递增负荷运动至乳酸阈强度,分别于运动前和乳酸阈强度下测定人体组及大鼠组静脉血氧分压、丙酮酸和乳酸含量。结果:(1)人体组和大鼠组在乳酸阈强度下,氧分压平均值分别是33.55±6.49mmHg(不吸氧)、31.86±6.23mmHg(补充吸氧)和58.64±2.01mmHg(不吸氧)、54.82±7.27mmHg(补充吸氧);血乳酸平均值分别是3.61±0.56mmol/L(不吸氧)、3.72±0.58mmol/L(补充吸氧)和5.43±0.55mmol/L(不吸氧)、5.35±0.50mmol/L(补充吸氧)。人体组和大鼠组运动前及乳酸阈强度下,丙酮酸平均值分别是0.97±0.17mmol/L、1.04±0.16mmol/L和0.93±0.25mmol/L、0.91±0.37mmol/L。(2)在乳酸阈强度下,不论是否吸氧,人体组和大鼠组血乳酸含量与氧分压之间均不相关,整个测试过程中人体组血氧饱和度均不低于98%;而二者血乳酸与血丙酮酸含量之间均呈高度显著性差异(P<0.001);二者运动前与乳酸阈强度时的血丙酮酸含量均无显著性差异(P>0.05)。结果表明,运动中由有氧向无氧代谢转变时体内不缺氧,本实验结果在整体水平上支持了糖酵解时丙酮酸转变成乳酸入血,以防止其堆积的观点。

Purpose To investigate the mechanism of metabolic conversion. Methods Twenty four college PE students exercised on cycle ergometer and 30 SD rats swam in water pool respectively. Incremental protocol was used to determine their transition point from aerobic to anaerobic metabolism. Partial pressure of venous oxygen, pyruvate and lactic acid were measured before exercise and during exercise. Results （1） The partial pressure of venous oxygen were 33.55±6.49mmHg and 58.64 ±2.01 mmHg; the blood lactic acid were 3.61±0.56mmol/L and 5.43± 0.55mmol/L, and the pyruvate were 1.04±0.16mmol/L and 0.91±0.37 mmol/L respectively in human body and rat at the level of lactic acid threshold. （2） The pyruvate before exercise and during exercise at the level of lactic acid threshold in human body and rat were 0.97±0.17mmol/L and 1.04±0.16mmol/L, and 0.93±0.25mmol/L and 0.91±0.37mmol/L, respectively. （3） There was no correlation between blood lactic acid and oxygen partial pressure in human body and rat （r = 0.31 ） at the level of lactic acid threshold; while the values of blood lactic acid and blood pyruvate between human and rat were significantly different during exercise at the level significantly difference between blood lactic acid no significance before loading and at oxygen was higher than 98 % during of lactic acid threshold （ P 〈 0.001 ）. However, there was and blood pyruvate （P 〈 0.001）, the pyruvate level showed the level of lactic acid threshold （ P 〉 0.05 ）, The saturation of blood the entire exercise course. Conclusion Results showed that there was no oxygen deficit during metabolic conversion （from aerobic to anaerobic metabolism）, and supported the hypothesis that pyruvate could transform into blood lactic acid in the course of glycolysis metabolism to prevent its accumulation.