Journal of Endocrinological Investigation

, Volume 26, Issue 9, pp 851–854 | Cite as

Metabolic response to exercise

  • P. De FeoEmail author
  • C. Di Loreto
  • P. Lucidi
  • G. Murdolo
  • N. Parlanti
  • A. De Cicco
  • F. Piccioni F Santeusanio


At the beginning, the survival of humans was strictly related to their physical capacity. There was the need to resist predators and to provide food and water for life. Achieving these goals required a prompt and efficient energy system capable of sustaining either high intensity or maintaining prolonged physical activity. Energy for skeletal muscle contraction is supplied by anaerobic and aerobic metabolic pathways. The former can allow short bursts of intense physical activity (60-90 sec) and utilizes as energetic source the phosphocreatine shuttle and anaerobic glycolysis. The aerobic system is the most efficient ATP source for skeletal muscle. The oxidative phosporylation of carbohydrates, fats and, to a minor extent, proteins, can sustain physical activity for many hours. Carbohydrates are the most efficient fuel for working muscle and their contribution to total fuel oxidation is positively related to the intensity of exercise. The first metabolic pathways of carbohydrate metabolism to be involved are skeletal muscle glycogenolysis and glycolysis. Later circulating glucose, formed through activated gluconeogenesis, becomes an important energetic source. Among glucose metabolites, lactate plays a primary role as either direct or indirect (gluconeogenesis) energy source for contracting skeletal muscle. Fat oxidation plays a primary role during either low-moderate intensity exercise or protracted physical activity (over 90-120 min). Severe muscle glycogen depletion results in increased rates of muscle proteolysis and branched chain amino acid oxidation. Endurance training ameliorates physical performance by improving cardiopulmonary efficiency and optimizing skeletal muscle supply and oxidation of substrates. 2003, Editrice Kurtis


Metabolism lactate glucose free fatty acids flux. 


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  1. 1.
    Stryer L. Biochemistry. New York: WH Freeman and Co. 1995, 441–682.Google Scholar
  2. 2.
    Brooks GA. Mammalian fuel utilization during sustained exercise. Comp Biochem Physiol 1998, 120: 89–107.CrossRefGoogle Scholar
  3. 3.
    Christensen EH, Hansen O. Arbeitsfahigkeit und ehrna-hrung. Sand Arch Physiol 1939, 81: 160–3.CrossRefGoogle Scholar
  4. 4.
    O’Brien MJ, Viguie CA, Mazzeo RS, et al. Carbohydrate dependence during marathon running. Med Sci Sports Exerc 1993, 25: 1009–17.PubMedCrossRefGoogle Scholar
  5. 5.
    Williams C. Physiological responses to exercise. In: Burr B Nagi D eds. Exercise and Sport in Diabetes. Chichester: John Wiley & Sons. 1999, 1.Google Scholar
  6. 6.
    Davies KJA, Packer L, Brooks GA. Biochemical adaptation of mitochondria, muscle and whole animal respiration to endurance training. Arch Biochem Biophys 1981, 209: 539–54.PubMedCrossRefGoogle Scholar
  7. 7.
    O’Doherty RM, Bracy DP, Granner DK, et al. Transcription of the rat skeletal muscle hexokinase II gene is increased by acute exercise. J Appl Physiol 1996, 81: 789–93.PubMedGoogle Scholar
  8. 8.
    Dudley G.A., Tullson P.C., Terjung R.L. Influence of mitochondrial content on the sensitivity of respiratory control. J. Biol. Chem. 1987, 262: 9109–9114.PubMedGoogle Scholar
  9. 9.
    Friedlander AL, Casazza GA, Huie MJ, et al. Endurance training alters glucose kinetics in response to the same absolute, but not the same relative workload. J Appl Physiol 1997, 82: 1360–9.PubMedGoogle Scholar
  10. 10.
    Philips SM, Green HJ, Tarnopolsky MA, et al. Effects of training duration on substrate turnover and oxidation during exercise. J Appl Physiol 1996, 81: 2182–8.Google Scholar
  11. 11.
    Hamdy O, Goodyear LJ, Horton ES. Diet and exercise in type 2 diabetes mellitus. Endocrinol Metab Clin North Am 2001, 30: 883–907.PubMedCrossRefGoogle Scholar
  12. 12.
    Merrill GF, Kurth EJ, Hardie DG, et al. AICA riboside increases AMP-activated protein kinase, fatty acid oxidation, and glucose uptake in rat muscle. Am J Physiol 1997, 273: E1107–12.PubMedGoogle Scholar
  13. 13.
    Balon T, Nadler J. Evidence that nitric oxide increases glucose transport in skeletal muscle. J Appl Physiol 1997, 82: 359–63.PubMedGoogle Scholar
  14. 14.
    Roberts C, Barnard R, Scheck S, et al. Exercise stimulated glucose transport in skeletal muscle is nitric oxide dependent. Am J Physiol 1997, 273: E220–5.PubMedGoogle Scholar
  15. 15.
    Hill AV, Long CHN, Lupton H. Muscular exercise, lactic acid and the supply and utilization of oxygen. I-III Proc R Soc London (Biol) 1924, 97: 84–176.CrossRefGoogle Scholar
  16. 16.
    Jsöbsis FF, Stainsby WN. Oxidation of NADH during contractions of circulated skeletal muscle. Resp Physiol 1968, 4: 292–300.CrossRefGoogle Scholar
  17. 17.
    Connett RJ, Gayeski TEJ, Honig CR. Lactate accumulation in fully aerobic, working, dog gracilis muscle. Am J Physiol 1984, 246: H120–8.PubMedGoogle Scholar
  18. 18.
    Welch HG, Stainsby WN. Oxygen debt in contracting dog skeletal muscle in situ. Resp Physiol 1967, 3: 229–42.CrossRefGoogle Scholar
  19. 19.
    Brooks GA, Butterfield GE, Wolfer RR, et al. Decreased reiance on lactate during exercise after acclimatization to 4300 m. J Appl Phsiol 1991, 71: 333–41.Google Scholar
  20. 20.
    Depocas F, Minaire Y, Chatonnet T. Rates of formation and oxidation of lactic acid in dogs at rest and during moderate exercise. Can J Physiol Pharmacol 1969, 47: 603–10.PubMedCrossRefGoogle Scholar
  21. 21.
    Roth DA, Brooks GA. Lactate transport is mediated by a membrane-borne carrier in rat skeletal muscle sarcolemma vesicles. Arch Biochem Biophys 1990, 279: 377–85.PubMedCrossRefGoogle Scholar
  22. 22.
    Kline ES, Brandt RB, Laux JE, et al. Localization of L-lactate dehydrogenase in mitochondria. Arch Biochem Biophys 1986, 246: 673–80.PubMedCrossRefGoogle Scholar
  23. 23.
    Laughlin MR, Taylor J, Chensnick AS, et al. Pyruvate and actate metabolism in the in vivo dog heart. Am J Physiol 1993, 264: H2068–79.PubMedGoogle Scholar

Copyright information

© Italian Society of Endocrinology (SIE) 2003

Authors and Affiliations

  • P. De Feo
    • 1
    Email author
  • C. Di Loreto
    • 1
  • P. Lucidi
    • 1
  • G. Murdolo
    • 1
  • N. Parlanti
    • 1
  • A. De Cicco
    • 1
  • F. Piccioni F Santeusanio
    • 1
  1. 1.Department of Internal Medicine, Section of Internal Medicine, Endocrine and Metabolic SciencesUniversity of PerugiaPerugiaItaly

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