Influence of training status on plasma volume variations and plasma lactate concentrations in response to supramaximal exercise

Abstract

Several studies have observed higher plasma lactate concentrations ([La]p) in sprinters compared to endurance trained or untrained subjects in response to sprint exercise. However the majority of these studies did not take into account the plasma volume variations (ΔVP) induced by supramaximal exercise which are found to be larger in sprinters. Consequently, we studied [La]p evolution in response to the Wingate test in sprinters (S), endurance trained (ET) and untrained subjects (UT) with regard to the changes in plasma volume (PV). 6 S (21±0.9 yrs), 6 ET (21.2±0.7 yrs) and 6 UT (21.5±0.6 yrs) male subjects participated in this study. The hematocrit and [La]p were measured from venous blood at rest, at the end of the Wingate test and after 5, 10, 20 and 30 min of recovery. The ΔVP was determined by taking into account the hematocrit variations. [La]p were corrected with regard to the changes in PV. The Wingate test was accompanied by a significant decrease in PV, the maximal values were - 19.97±3.05 % in S, -9.45±3.05 % in ET and -9.05±3.31 % in UT. This decrease was significantly higher in S than in ET and UT at the end of the test and after 5 min induced an overestimation of the maximal values of measured [La]p in the three groups: +18.7% in S (16.6±0.9 vs. 13.5±0.6 mmol·L-1), +18.8% in ET (12.2±0.9 vs. 9.9±1.8 mmol·L-1) and +6.5% in UT (12.3±1 vs. 11.5±1 mmol·L-1). In conclusion, these results underline the importance of taking into account the ΔVP to compare and to interpret [La]p and their evolution in response to supramaximal exercise between subjects with different training status.