Evaluation of the Lactate Threshold of Rats Using External Jugular Vein Catheterization

[Purpose] The purpose of the present study was to investigate if lactate thresholds in rats could be accurately determined from sequential blood lactate concentrations during incremental exercise tests. [Subjects] Six female Wistar rats were used in this study. [Methods] Catheters were inserted into the right external jugular veins of the rats before they performed the incremental exercise tests. To determine the lactate threshold, a graph was made from the results of the blood lactate concentrations at the different running speeds. [Results] It was possible to frequently and reliably measure blood lactate concentrations of the rats during incremental exercise tests and to determine lactate thresholds. The mean lactate concentration at the lactate threshold was 3.5 +/- 3.0 mmol/L, and the mean running speed was 18.0 +/- 2.8 (16.1-22.8) m/min [Conclusion] This study showed that it is possible to accurately determine the lactate threshold by taking sequential blood samples during incremental exercise tests.