Effect of high-intensity exercise training on lactate/H1 transport capacity in human skeletal muscle HENRIETTE PILEGAARD,1 KRISTIAN DOMINO,1 THOMAS NOLAND,1 CARSTEN JUEL,1 YLVA HELLSTEN,1 ANDREW P. HALESTRAP,2 AND JENS BANGSBO1

Pilegaard, Henriette, Kristian Domino, Thomas Noland, Carsten Juel, Ylva Hellsten, Andrew P. Halestrap, and Jens Bangsbo. Effect of high-intensity exercise training on lactate/H1 transport capacity in human skeletal muscle. Am. J. Physiol. 276 (Endocrinol. Metab. 39): E255– E261, 1999.—The present study examined the effect of highintensity exercise training on muscle sarcolemmal lactate/H1 transport and the monocarboxylate transporters (MCT1 and MCT4) as well as lactate and H1 release during intense exercise in humans. One-legged knee-extensor exercise training was performed for 8 wk, and biopsies were obtained from untrained and trained vastus lateralis muscle. The rate of lactate/H1 transport determined in sarcolemmal giant vesicles was 12% higher (P , 0.05) in the trained than in untrained muscle (n 5 7). The content of MCT1 and MCT4 protein was also higher (76 and 32%, respectively; n 5 4) in trained muscle. Release of lactate and H1 from the quadriceps muscle at the end of intense exhaustive knee-extensor exercise was similar in the trained and untrained leg, although the estimated muscle intracellular-to-interstitial gradients of lactate and H1 were lower (P , 0.05) in the trained than in the untrained muscle. The present data show that intense exercise training can increase lactate/H1 transport capacity in human skeletal muscle as well as improve the ability of the muscle to release lactate and H1 during contractions.