摄取NaHCO_3对渐增负荷运动时血浆胺和乳酸浓度的影响

Influence of NaHCO3 Intake on Plasma Ammonia and LactateConcentration During Incremental Exercise

本研究的目的是调查在渐增负荷运动中，血浆胺和血浆乳酸浓度是否受细胞外液碱中毒的影响，以及乳酸阈（ＬＴ）和通气闲（ＶＴ）也是否受其影响；８名受试者采用功率自行车进行渐增负荷运动，直至力竭。同时测定吸氧量（ＶＯ２）、通气量（ＶＥ）、血浆乳酸、血浆胺、血液ｐＨ、ＨＣＯ３－及心率（ＨＲ）。受试者在两种条件下进行实验：（１）每公斤体重摄取０．３ａＮａＨＣＯｄ３（碱中毒组：Ａ）；（２）摄取安慰胶囊组（Ｐ）。运动前后的血液ｐＨ和ＨＣＯ３－均有显著性差异。Ａ组与Ｐ组相比较，运动负荷时间及ＶＯ２ｍａｘ无显著性差异（ｐ＞０．０５）。Ｐ组ＬＴ时的ＶＯ２与ＶＴ相比较，无显著性差异（ｐ＞０．０５），但Ａ组ＬＴ时的ＷＯ２与ＶＴ相比较，却有显著性差异（ｐ＜０．０５）。Ａ组和Ｐ组ＶＴ时的ＶＯ２相比较，无显著性差异（ｐ＞０．０５），但两组ＬＴ时的ＶＯ２相比较，有显著性差异（ｐ＜０．０５。Ａ组ＬＴ明显低于Ｐ组，反映了在运动中大量乳酸由肌肉进入血液。Ａ组和Ｐ组的血浆胺阈（ＡＭＴ）相比较，无显著性差异（ｐ＞０．０５），研究证明细胞外碱中毒影响ＬＴ而不影响ＡＭＴ，使ＬＴ和ＶＴ分离，从而影响ＬＴ的确定。

The purpose of this study was to investigate whether the levels of plasma ammonia and lactate concentration were affected by ex- tracellular alkalosis,and by the lactate threshold(LT)or ventilatory threshold(VT) during incremental exercise.Oxygen consumption (VO2),pulmonary ventilation(VE),plasma lactate,plasma ammonia,blood pH,HCo3 and heart rate (HR)were obtaine during incremental exercise to exhaustion on a bicycle ergometer for 8 men under the following conditions:1)After the intake of NaHCo3(0. 3 g per 1kg body weight)-alkalosis Group (A).2)After the intake of placebo gel(Group P).Blood pH and HCo3 were significantly higher before and after the experiment.The performance time and Vo2 max did not differ significantly for Group A and P.Vo2 at LT and VT for Group P were not significantly different,while there were for Group A.The Vo2 at VT for both groups showed no signifi- cant difference,while Vo2 at LT was significantly lower for Group A than that for Group P.The later reflected greater lactate diffusion from muscle into blood.The VO2 at the plasma AMTs for the two groups did not differ significantly.These data demonstrated that plasma LT can be affected by extracellular alkalosis,but the plasma AMT can not be influenced.We were able to demonstrate disso- ciation of LT and VT as a result of NaHCO3 intake.Specially,NaHCO3 affects the determination of LT.