CONTINUOUS MONITORING OF LACTATE DURING EXERCISE IN HUMANS USING SUBCUTANEOUS AND TRANSCUTANEOUS MICRODIALYSIS

We have evaluated the possibility of monitoring the plasma lactate con centration in human volunteers during cycle ergometer exercise using s ubcutaneous and transcutaneous microdialysis. In transcutaneous microd ialysis, the relative increase in dialysate lactate concentration exce eded that of plasma lactate concentration by a factor of 6 during exer cise due to exercise-induced lactate secretion in sweat. During exerci se the subcutaneous microdialysis dialysate lactate concentration unde restimated the plasma lactate concentration possibly due to diffusion limitation or adipose tissue lactate production. While it was demonstr ated that microdialysis can be used for on-line lactate monitoring, ne ither subcutaneous nor transcutaneous dialysate lactate concentration were linearly related to the plasma lactate concentration during exerc ise, and it was found therefore that it was not possible to monitor di rectly plasma lactate concentration during exercise.