Plasma lactate recovery from maximal exercise with correction for variations in plasma volume.
BACKGROUND
To compare plasma lactate concentrations and plasma lactate kinetics during recovery, for measured and corrected values for changes in plasma volume, after a maximal aerobic exercise.


METHODS
Sixteen male subjects performed an incremental and maximal exercise in order to reach maximal aerobic power. Prior to the exercise, at the end and during recovery (2, 5, 12 and 30 min), blood samples were collected through an antecubital catheter. Samples were analysed for lactate, hematocrit and hemoglobin in order to calculate changes in plasma volume. Plasma lactate concentrations ([La]p) were corrected for changes in plasma volume. Plasma lactate kinetics was estimated through the ratio between [La]p after 5 min recovery minus [La]p after 30 min to time (25 min) and expressed in percentage per minute.


RESULTS
Maximal changes in plasma volume (-19.7 +/- 3.8%) were correlated to maximal measured [La]p (r=0.66, p<0.01). Maximal measured [La]p values (14.9 +/- 2.6 mmol x l-1) were 17.3% higher (p<0.001) than corrected values (12.7 +/-2.0 mmol x l-1). The kinetics of [La]p decrease was significantly higher (p<0.001) for measured values (2.38 +/- 0.29 % x min-1) than for corrected values (2.22 +/- 0.33 % x min-1).


CONCLUSIONS
These results suggested that changes in plasma volume must be taken into account when peak postexercise plasma lactate concentration or lactate recovery curves are analysed.
Berthoin
S
S
Laboratoire d'Etudes de la Motricité Humaine, Faculté des Sciences du Sport et de l'Education Physique, Université de Lille 2, Lille, France. berthoin@hp-sc.univ.lille2.fr
Pelayo
P
P
Baquet
G
G
Marais
G
G
Allender
H
H
Robin
H
H
D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010807:Physical Endurance / Q000502:physiology; D010953:Plasma Volume / Q000502:physiology*; D020127:Recovery of Function / Q000502:physiology; D013177:Sports / Q000502:physiology*
D019344:Lactic Acid