Prediction of individual oxygen uptake on-step transients from frequency responses

  • Uwe Hoffmann
  • Dieter Eβfeld
  • Dieter Leyk
  • Hans-Georg Wunderlich
  • Jürgen Stegemann
Original Articles

Abstract

Power-oxygen uptake (\(\dot V{\text{O}}_{\text{2}} \)) frequency responses can be used to predict\(\dot V{\text{O}}_{\text{2}} \) responses to arbitrary exercise intensity patterns. It is still an open question for which range of exercise intensities such computed\(\dot V{\text{O}}_{\text{2}} \) response patterns yield valid predictions. In the present study, we determined the power-\(\dot V{\text{O}}_{\text{2}} \) frequency response of nine sports students by means of pseudo-randomised switching between 20 W and 80 W during upright and supine cycle exercise. Starting from a baseline of 20 W each subject also performed sustained step increases to 40 W, 80 W, 120 W, and 160 W in both positions. The individual\(\dot V{\text{O}}_{\text{2}} \) step responses were then compared with the expected\(\dot V{\text{O}}_{\text{2}} \) time-courses predicted on the basis of the individual\(\dot V{\text{O}}_{\text{2}} \) frequency responses. The comparison showed a close agreement for the 20 W–40 W and 20 W–80 W steps in both positions. With larger step amplitudes the\(\dot V{\text{O}}_{\text{2}} \) kinetics became increasingly slower than the predicted\(\dot V{\text{O}}_{\text{2}} \) time course in both positions. During additional ramp tests (10 W · 30 s−1) whole blood lactic acid concentration [1a]b tended to be higher in the supine position at exercise intensities higher than 160 W. The mean power at 4 mmol · 1−1 [la]b amounted to 234 (SD 32) W and 253 (SD 44) W (P<5%) in the supine and the upright position, respectively. The maximal oxygen uptake relative to body mass was not found to be significantly different [upright, mean 57 (SD 10) ml · (min · kg)−1;supine, mean 54 (SD 10) ml · (min · kg)]. These findings would suggest that for a range of mild exercise intensities\(\dot V{\text{O}}_{\text{2}} \) kinetics are not appreciably influenced by the step amplitude or by cardiovascular changes associated with the upright and the supine position.

Key words

Oxygen uptake kinetics Cycle exercise Body position Pseudo-randomised changes of exercise intensity Step response 

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References

  1. Barstow TJ, Casaburi R, Wasserman K (1993) O2 uptake kinetics and the O2 deficit as related to exercise intensities and blood lactate. J Appl Physiol 75:755–762Google Scholar
  2. Casaburi R, Barstow TJ, Robinson T, Wasserman K (1989) Influence of work rate on ventilatory and gas exchange kinetics. J Appl Physiol 67:547–555Google Scholar
  3. Cerretelli P, Rennie DW, Pendergast DP (1980) Kinetics of metabolic transients during exercise. Int J Sports Med 1:171–180Google Scholar
  4. Cochrane JE, Hughson RL (1992) Computer simulation of O2 transport and utilization mechanisms at the onset of exercise. J Appl Physiol 73:2382–2388Google Scholar
  5. Convertino VA, Goldwater DJ, Sandler H (1984) Oxygen uptake kinetics of constant-load work: upright vs. supine exercise. Aviat Space Environ Med 55:501–505Google Scholar
  6. E\feld D, Hoffmann U, Stegemann J (1987)\(\dot V{\text{O}}_{\text{2}} \) kinetics in subjects differing in aerobic capacity: investigation by spectral analysis. Eur J Appl Physiol 56:508–515Google Scholar
  7. E\feld D, Hoffmann U, Stegemann J (1991) A model for studying the distortion of muscle oxygen uptake patterns by circulation parameters. Eur J Appl Physiol 62:83–90Google Scholar
  8. Hoffmann U, E\feld D, Stegemann J, Schütze H (1991) Comparison of\(\dot V{\text{O}}_{\text{2}} \) kinetics in upright and supine position. Acta Astron 23:135–137Google Scholar
  9. Hoffmann U, E\feld D, Wunderlich HG, Stegemann J (1992) Dynamic linearity of\(\dot V{\text{O}}_{\text{2}} \) responses during aerobic exercise. Eur J Appl Physiol 64:139–144Google Scholar
  10. Hughson RL, Xing HC, Borkhoff C, Butler G (1991) Kinetics of ventilation and gas exchange during supine and upright cycle exercise. Eur J Appl Physiol 63:300–307Google Scholar
  11. Kowalchuk JM, Hughson RL (1990) Effect of β-adrenergic blockade on VO2 kinetics during pseudorandom binary sequence exercise. Eur J Appl Physiol 60:365–369Google Scholar
  12. Leyk D, Hoffmann U, Baum K, Stegemann J (1992) Influence of body position and pre-exercise activity on cardiac output and oxygen uptake following step changes in exercise intensity. Eur J Appl Physiol 65:499–506Google Scholar
  13. Sietsema KE, Daly JA, Wasserman K (1989) Early dynamics of O2 uptake and heart rate as affected by exercise work rate. J Appl Physiol 67:2535–2541Google Scholar
  14. Stegemann J, E\feld D, Hoffmann U (1985) Effects of a 7-day headdown tilt (−6°) on the dynamics of oxygen uptake and heart rate adjustment in upright exercise. Aviat Space Environ Med 56:410–414Google Scholar
  15. Xing HC, Cochrane JE, Yamamoto Y, Hughson RL (1991) Frequency domain analysis of ventilation and gas exchange kinetics in hypoxic exercise. J Appl Physiol 71:2394–2401Google Scholar

Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Uwe Hoffmann
    • 1
    • 1
  • Dieter Eβfeld
    • 1
  • Dieter Leyk
    • 1
  • Hans-Georg Wunderlich
    • 1
  • Jürgen Stegemann
    • 1
  1. 1.Physiologisches Institut der Deutschen Sporthochschule KölnCologneGermany

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