Modeling the blood lactate kinetics at maximal short-term exercise conditions in children, adolescents, and adults

• Published in: Journal of applied physiology (1985) 2005-08, Vol.99 (2), p.499-504
• Main Authors: Beneke, Ralph, Hutler, Matthias, Jung, Marcus, Leithauser, Renate M
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age differences; Aging - physiology; Biological and medical sciences; Blood; Child; Computer Simulation; Exercise; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Lactic Acid - blood; Male; Metabolic Clearance Rate; Models, Biological; Muscle, Skeletal - physiology; Physical Endurance - physiology; Physical Exertion - physiology; Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00062.2005

1 Centre for Sports and Exercise Science, Department of Biological Sciences, University of Essex, Colchester, United Kingdom; 2 Department of Physical Medicine and Rehabilitation, Haukeland University Hospital, Bergen, Norway; and 3 Institute of Sports Medicine, Free University, Berlin, Germany Submitted 18 January 2005 ; accepted in final form 22 March 2005 Whether age-related differences in blood lactate concentrations (BLC) reflect specific BLC kinetics was analyzed in 15 prepubescent boys (age 12.0 ± 0.6 yr, height 1.54 ± 0.06 m, body mass 40.0 ± 5.2 kg), 12 adolescents (16.3 ± 0.7 yr, 1.83 ± 0.07 m, 68.2 ± 7.5 kg), and 12 adults (27.2 ± 4.5 yr, 1.83 ± 0.06 m, 81.6 ± 6.9 kg) by use of a biexponential four-parameter kinetics model under Wingate Anaerobic Test conditions. The model predicts the lactate generated in the extravasal compartment (A), invasion ( k 1 ), and evasion ( k 2 ) of lactate into and out of the blood compartment, the BLC maximum (BLC max ), and corresponding time (TBLC max ). BLC max and TBLC max were lower ( P < 0.05) in boys (BLC max 10.2 ± 1.3 mmol/l, TBLC max 4.1 ± 0.4 min) than in adolescents (12.7 ± 1.0 mmol/l, 5.5 ± 0.7 min) and adults (13.7 ± 1.4 mmol/l, 5.7 ± 1.1 min). No differences were found in A related to the muscle mass (A MM ) and k 1 between boys (A MM : 22.8 ± 2.7 mmol/l, k 1 : 0.865 ± 0.115 min –1 ), adolescents (22.7 ± 1.3 mmol/l, 0.692 ± 0.221 min –1 ), and adults (24.7 ± 2.8 mmol/l, 0.687 ± 0.287 min –1 ). The k 2 was higher ( P < 0.01) in boys (2.87 10 –2 ± 0.75 10 –2 min –1 ) than in adolescents (2.03 x 10 –2 ± 0.89 x 10 –2 min –1 ) and adults (1.99 x 10 –2 ± 0.93 x 10 –2 min –1 ). Age-related differences in the BLC kinetics are unlikely to reflect differences in muscular lactate or lactate invasion but partly faster elimination out of the blood compartment. glycolysis; extravasal compartment; invasion; elimination Address for reprint requests and other correspondence: R. Beneke, Dept. of Biological Sciences, Univ. of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom (E-mail: rbeneke{at}essex.ac.uk )