Lactate kinetics at the lactate threshold in trained and untrained individuals

We are pleased to introduce the abstract of the article written by Messonnier LA, Emhoff CW, Fattor JA, Horning MA, Carlson and TJ, Brooks GA with the original title “Lactate kinetics at the lactate threshold in trained and untrained men”. This article was published in 2013 by Journal of Applied Physiology 114: 1593–1602

“To understand the meaning of the lactate threshold (LT) and to test the hypothesis that endurance training augments lactate kinetics [i.e., rates of appearance and disposal (Ra and Rd, respectively, mg·kg-1·min-1) and metabolic clearance rate (MCR, ml· kg-1·min-1)], we studied six untrained (UT) and six trained (T) subjects during 60-min exercise bouts at power outputs (PO) eliciting the LT. Trained subjects performed two additional exercise bouts at a PO 10% lower (LT-10%), one of which involved a lactate clamp (LC) to match blood lactate concentration ([lactate]b) to that achieved during the LT trial. At LT, lactate Ra was higher in T (24.1 ± 2.7) than in UT (14.6 ± 2.4; P < 0.05) subjects, but Ra was not different between UT and T when relative exercise intensities were matched (UT-LT vs. T-LT-10%, 67%VO2max). At LT, MCR in T (62.5 ± 5.0) subjects was 34% higher than in UT (46.5 ± 7.0; P < 0.05), and a reduction in PO resulted in a significant increase in MCR by 46% (LT-10%, 91.5 ± 14.9, P <0.05). At matched relative exercise intensities (67% VO2max), MCR in T subjects was 97% higher than in UT (P < 0.05). During the LC trial, MCR in T subjects was 64% higher than in UT (P < 0.05), in whom % VO2max and [lactate]b were similar. We conclude that:

  1. Lactate MCR reaches an apex below the LT,
  2. LT corresponds to a limitation in MCR, and
  3. Endurance training augments capacities for lactate production, disposal and clearance.”

Please click here to access the original article: Lactate kinetics at the lactate threshold in trained and untrained men