The\(\dot VCO_2 \)/\(\dot VO_2 \) relationship during heavy, constant work rate exercise reflects the rate of lactic acid accumulation

  • William Stringier
  • Karlman Wasserman
  • Richard Casaburi
Original Article


Oxygen uptake (\(\dot VO_2 \)) kinetics have been reported to be modified when lactic acid accumulates; however little attention has been given to the simultaneous carbon dioxide production (\(\dot VCO_2 \)>) kinetics. To demonstrate how\(\dot VCO_2 \) changes as a function of\(\dot VO_2 \) when lactic acid is buffered by bicarbonate, eight healthy subjects performed 6-min constant work rate cycle ergometer exercise tests at moderate, heavy and very heavy exercise intensities.\(\dot VCO_2 \) and\(\dot VO_2 \) were measured breath-by-breath, and arterial blood samples were obtained every 7.5 s during the first 3 min of exercise, and were analyzed for pH, partial pressure of carbon dioxide, standard bicarbonate, and lactate.\(\dot VCO_2 \) abruptly increased relative to\(\dot VO_2 \) between 40 and 50 s after the start of exercise for the high exercise intensities. These gas exchange events were observed to correlate well with the time and\(\dot VO_2 \) at which lactic acid increased and plasma bicarbonate decreased (r = 0.90,r = 0.95, respectively). We conclude that bicarbonate buffering of lactic acid can be determined from the acceleration of\(\dot VCO_2 \) relative to\(\dot VO_2 \) kinetics in response to constant work rate exercise and the increase is quantitatively related to the magnitude of the lactic acid increase. This is easily visualized from a plot of\(\dot VCO_2 \) as a function of\(\dot VO_2 \).

Key words

Oxygen uptake kinetics Carbon dioxide output kinetics Lactate Standard bicarbonate Arterial blood gases 


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  1. Beaver WL, Lamarra N, Wasserman K (1981) Breath-by-breath measurement of true alveolar gas exchange. J Appl Phyisol 51:1662–1675Google Scholar
  2. Beaver WL, Wasserman K, Whipp BJ (1986a) A new method for detecting anaerobic threshold by gas exchange. J Appl Physiol 60:2020–2027Google Scholar
  3. Beaver WL, Wasserman K, Whipp BJ (1986b) Bicarbonate buffering of lactic acid generated during exercise. J Appl Physiol 60:472–478Google Scholar
  4. Casaburi R, Barstow T, Robinson T, Wasserman K (1989a) Influence of work rate on ventilatory and gas exchange kinetics. J Appl Physiol 67:547–555Google Scholar
  5. Casaburi R, Daly J, Hansen J, Effros P (1989b) Abrupt changes in mixed venous blood gas composition after the onset of exercise. J Appl Physiol 67:1106–1112Google Scholar
  6. Casaburi R, Barstow TL, Robinson T, Wasserman K (1992) Dynamic and steady-state ventilatory and gas exchange responses to arm exercise. Med Sci Sports Exerc 24:1365–1374Google Scholar
  7. Cerretelli PD, Pendergast D, Paganelli WC, Rennie DW (1979) Effects of specific muscle training on\(\dot VO_2 \) on-response and early blood lactate. J Appl Physiol 47:761–769Google Scholar
  8. Cerretelli PD, Rennie DW, Pendergast D (1980) Kinetics of metabolic transients during exercise. Int J Sports Med 1:171–180Google Scholar
  9. Clode M, Cambell EJM (1969) The relationship between gas exchange and changes in blood lactate concentration during exercise. Clin Sci 37:263–272Google Scholar
  10. Di Prampero PE (1981) Energetics of muscular exercise. Rev Physiol Biochem Pharmacol 89:43–222Google Scholar
  11. Harrison TR, Pilcher (1930) Studies in congestive heart failure. II. The respiratory exchange during and after exercise. J Clin Invest 8:291–315Google Scholar
  12. Klocke RA (1987) Carbon dioxide transport. In: Farht GE, Tenney SM (eds) The respiratory system, vol IV (Chap 10) (Handbook of physiology, section 3). American Physiological Society, Bethesda pp 173–197Google Scholar
  13. Linnarsson D (1974) Dynamics of pulmonary gas exchange and heart rate changes at start and end of exercise. Acta Physiol Scand 415:1–68Google Scholar
  14. Naimark A, Wasserman K, McIlroy MB (1964) Continuous measurement of ventilatory exchange ratio during exercise: A test of cardiovascular function. J Appl Physiol 19:644Google Scholar
  15. Olsen C (1971) An enzymatic fluorimetric micromethod for determination of acetoacetate, beta-hydroxybuterate, pyruvate and lactate. Clin Chem Acta 33:293–300Google Scholar
  16. Seldinger SI (1953) Catheter replacement of the needle in percutaneous arteriography: a new technique. Acta Radiol 39:368–376Google Scholar
  17. Sue DY, Wasserman K, Moricca RB, Casaburi R (1988) Metabolic acidosis during exercise in patients with chronic obstructive pulmonary disease. Chest 94:931–938Google Scholar
  18. Stringer WW, Casaburi R, Wasserman K (1992) Acid-base regulation during exercise and recovery in humans. J Appl Physiol 72:954–961Google Scholar
  19. Wasserman K, Casaburi R (1991) Acid-base regulation during exercise in humans. In: Whipp BJ, Wasserman K (eds) Exercise-pulmonary physiology and pathophysiology. Dekker, New York, pp 405–448Google Scholar
  20. Wasserman K, McIlroy MB (1964) Detecting the threshold of anaerobic metabolism in cardiac patients during exercise. Am J Cardiol 14:844–852Google Scholar
  21. Wasserman K, Hansen JE, Sue DY, Whipp BJ, Casaburi R (1994) Principles of exercise testing and interpretation, 2nd edn. Lea and Febiger, PhiladelphiaGoogle Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • William Stringier
    • 1
  • Karlman Wasserman
    • 1
  • Richard Casaburi
    • 1
  1. 1.Division of Respiratory and Critical Care, Physiology and MedicineHarbor-UCLA Medical CenterTorranceUSA

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