title: Lactate kinetics at the lactate threshold in trained and untrained men.
abstract: 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.
authors.affiliation: Exercise Physiology Laboratory, Department of Integrative Biology, University of California Berkeley, Berkeley, California 94720-3140, USA.
authors.forename: Laurent A
authors.initials: LA
authors.lastname: Messonnier
authors.forename: Chi-An W
authors.initials: CA
authors.lastname: Emhoff
authors.forename: Jill A
authors.initials: JA
authors.lastname: Fattor
authors.forename: Michael A
authors.initials: MA
authors.lastname: Horning
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Carlson
authors.forename: George A
authors.initials: GA
authors.lastname: Brooks
mesh_terms: D015308:Anaerobic Threshold / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008657:Metabolic Clearance Rate; D010101:Oxygen Consumption / Q000502:physiology*; D064797:Physical Conditioning, Human / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D055815:Young Adult
chemical_list: D019344:Lactic Acid
keywords: endurance training; exercise; gluconeogenesis from lactate; intermediary metabolism; lactate oxidation; maximal lactate steady state (MLSS), exertion
references.citation: Am J Physiol Regul Integr Comp Physiol. 2012 Jan 1;302(1):R143-9
references.pmid: 22031785
references.citation: J Am Coll Cardiol. 1997 Apr;29(5):1067-73
references.pmid: 9120161
references.citation: Int J Sports Med. 2005 Jun;26(5):376-82
references.pmid: 15895321
references.citation: Am J Physiol. 1999 Feb;276(2):E255-61
references.pmid: 9950784
references.citation: FASEB J. 2008 Oct;22(10):3443-9
references.pmid: 18653766
references.citation: J Cell Biol. 1971 Dec;51(3):621-35
references.pmid: 5128351
references.citation: Med Sci Sports Exerc. 1997 Mar;29(3):396-401
references.pmid: 9139180
references.citation: Circulation. 1980 Feb;61(2):256-61
references.pmid: 7351050
references.citation: J Appl Physiol (1985). 1985 Aug;59(2):320-7
references.pmid: 4030584
references.citation: J Physiol. 2002 Nov 1;544(3):963-75
references.pmid: 12411539
references.citation: J Appl Physiol (1985). 1992 Jun;72(6):2435-45
references.pmid: 1629100
references.citation: Am J Physiol. 1983 Jan;244(1):E83-92
references.pmid: 6401405
references.citation: J Appl Physiol (1985). 2007 Oct;103(4):1227-33
references.pmid: 17656631
references.citation: Arch Biochem Biophys. 1990 Jun;279(2):377-85
references.pmid: 2350184
references.citation: Acta Physiol Scand. 2001 Oct;173(2):195-205
references.pmid: 11683677
references.citation: Am J Physiol. 1998 Jan;274(1):E102-7
references.pmid: 9458754
references.citation: Am J Physiol Endocrinol Metab. 2005 Jan;288(1):E143-7
references.pmid: 15328074
references.citation: Am J Physiol Endocrinol Metab. 2002 Nov;283(5):E889-98
references.pmid: 12376315
references.citation: J Appl Physiol. 1975 Nov;39(5):718-23
references.pmid: 1184510
references.citation: Arch Biochem Biophys. 1987 Dec;259(2):412-22
references.pmid: 3426237
references.citation: Pflugers Arch. 1995 Oct;430(6):964-70
references.pmid: 8594549
references.citation: Am J Physiol Endocrinol Metab. 2000 Apr;278(4):E571-9
references.pmid: 10751188
references.citation: J Appl Physiol (1985). 1986 Sep;61(3):932-9
references.pmid: 3759777
references.citation: Am J Physiol Endocrinol Metab. 2003 Jan;284(1):E193-205
references.pmid: 12388120
references.citation: J Appl Physiol (1985). 1993 Aug;75(2):668-74
references.pmid: 8226467
references.citation: J Appl Physiol (1985). 1998 Feb;84(2):465-70
references.pmid: 9475854
references.citation: J Cereb Blood Flow Metab. 2009 Jun;29(6):1121-9
references.pmid: 19337275
references.citation: J Physiol. 2005 Aug 15;567(Pt 1):121-9
references.pmid: 15932892
references.citation: J Appl Physiol (1985). 2013 Feb;114(3):297-306
references.pmid: 23239870
references.citation: Am J Cardiol. 1964 Dec;14:844-52
references.pmid: 14232808
references.citation: Arch Biochem Biophys. 1986 May 1;246(2):673-80
references.pmid: 3518634
references.citation: Int J Sports Med. 1985 Jun;6(3):117-30
references.pmid: 4030186
references.citation: Am J Physiol. 1984 Sep;247(3 Pt 1):E380-4
references.pmid: 6383071
references.citation: J Appl Physiol (1985). 1992 May;72(5):1649-56
references.pmid: 1601768
references.citation: J Appl Physiol (1985). 1988 Jun;64(6):2622-30
references.pmid: 3403447
references.citation: Am J Physiol. 1982 Jan;242(1):E25-32
references.pmid: 7058885
references.citation: Cell. 1994 Mar 11;76(5):865-73
references.pmid: 8124722
references.citation: J Physiol. 1976 Jun;258(1):1-18
references.pmid: 940045
references.citation: Eur J Appl Physiol. 2001 May;84(5):403-12
references.pmid: 11417427
references.citation: J Appl Physiol (1985). 1994 Oct;77(4):1858-62
references.pmid: 7836210
references.citation: J Appl Physiol (1985). 1989 Jun;66(6):2710-6
references.pmid: 2745334
references.citation: Acta Physiol Scand Suppl. 1976;436:1-32
references.pmid: 803189
references.citation: J Physiol. 1995 Oct 1;488 ( Pt 1):219-29
references.pmid: 8568658
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1984 Sep;57(3):640-3
references.pmid: 6490453
references.citation: J Appl Physiol (1985). 1995 Dec;79(6):1862-9
references.pmid: 8847245
references.citation: Med Sci Sports Exerc. 1989 Feb;21(1):40-4
references.pmid: 2927300
references.citation: Am J Physiol Regul Integr Comp Physiol. 2011 Oct;301(4):R1078-87
references.pmid: 21775647
references.citation: Med Sci Sports Exerc. 1985 Feb;17(1):22-34
references.pmid: 3884959
references.citation: J Appl Physiol. 1972 May;32(5):690-4
references.pmid: 4556852
references.citation: Genomics. 1994 Sep 15;23(2):500-3
references.pmid: 7835905
references.citation: Proc Natl Acad Sci U S A. 1999 Feb 2;96(3):1129-34
references.pmid: 9927705
references.citation: J Appl Physiol (1985). 2002 Apr;92(4):1677-83
references.pmid: 11896037
references.citation: Am J Physiol. 1985 Dec;249(6 Pt 1):E595-602
references.pmid: 4083344
references.citation: Am J Physiol Endocrinol Metab. 2006 Jun;290(6):E1237-44
references.pmid: 16434551
references.citation: J Appl Physiol (1985). 1986 Nov;61(5):1693-700
references.pmid: 3536838
references.citation: J Clin Invest. 1986 Mar;77(3):690-9
references.pmid: 3512600
references.citation: Int J Sports Med. 1981 Feb;2(1):23-6
references.pmid: 7333732
references.citation: J Appl Physiol (1985). 2002 Apr;92(4):1573-84
references.pmid: 11896024
references.citation: Acta Physiol Scand. 1976 Jun;97(2):150-7
references.pmid: 949000
references.citation: Arch Biochem Biophys. 1990 Jun;279(2):386-94
references.pmid: 2350185
references.citation: Med Sci Sports Exerc. 2011 Oct;43(10):1849-56
references.pmid: 21448086
references.citation: Med Sci Sports Exerc. 2008 Mar;40(3):486-94
references.pmid: 18379211
references.citation: FASEB J. 2007 Aug;21(10):2602-12
references.pmid: 17395833
references.citation: J Physiol. 2001 Jul 1;534(Pt 1):269-78
references.pmid: 11433007
references.citation: J Clin Invest. 1964 Aug;43:1677-90
references.pmid: 14201551
references.citation: J Appl Physiol (1985). 1986 Jan;60(1):232-41
references.pmid: 3080398
references.citation: J Appl Physiol (1985). 1997 Apr;82(4):1360-9
references.pmid: 9104876
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1984 May;56(5):1260-4
references.pmid: 6725086
references.citation: J Appl Physiol (1985). 1999 Nov;87(5):1684-96
references.pmid: 10562610
references.citation: J Appl Physiol. 1965 May;20(3):384-94
references.pmid: 5319986
references.citation: Physiol Rev. 1997 Apr;77(2):321-58
references.pmid: 9114817
references.citation: Biochem Biophys Res Commun. 1978 Jul 14;83(1):151-7
references.pmid: 697805
references.citation: Med Sci Sports Exerc. 1986 Jun;18(3):360-8
references.pmid: 3523107
references.citation: Chest. 1992 May;101(5 Suppl):211S-218S
references.pmid: 1576837
references.citation: Metabolism. 1988 Sep;37(9):850-8
references.pmid: 3138512
references.citation: Am J Physiol Endocrinol Metab. 2000 Feb;278(2):E244-51
references.pmid: 10662708
references.citation: J Appl Physiol (1985). 1991 Jul;71(1):333-41
references.pmid: 1917759
references.citation: J Clin Invest. 1963 Jun;42:800-10
references.pmid: 14021827