Tags

Type your tag names separated by a space and hit enter

Oxygen uptake does not increase linearly at high power outputs during incremental exercise test in humans.
Eur J Appl Physiol Occup Physiol. 1998 Apr; 77(5):445-51.EJ

Abstract

A group of 12 healthy non-smoking men [mean age 22.3 (SD 1.1) years], performed an incremental exercise test. The test started at 30 W, followed by increases in power output (P) of 30 W every 3 min, until exhaustion. Blood samples were taken from an antecubital vein for determination of plasma concentration lactate [La-]pl and acid-base balance variables. Below the lactate threshold (LT) defined in this study as the highest P above which a sustained increase in [La-]pl was observed (at least 0.5 mmol x l[-1] within 3 min), the pulmonary oxygen uptake (VO2) measured breath-by-breath, showed a linear relationship with P. However, at P above LT [in this study 135 (SD 30) W] there was an additional accumulating increase in VO2 above that expected from the increase in P alone. The magnitude of this effect was illustrated by the difference in the final P observed at maximal oxygen uptake (VO2max) during the incremental exercise test (Pmax,obs at VO2max) and the expected power output at VO2max(Pmax,exp at VO2max) predicted from the linear VO2-P relationship derived from the data collected below LT. The Pmax,obs at VO2max amounting to 270 (SD 19) W was 65.1 (SD 35) W (19%) lower (P < 0.01) than the Pmax,exp at VO2max. The mean value of VO2max reached at Pmax,obs amounted to 3555 (SD 226) ml x min(-1) which was 572 (SD 269) ml x min(-1) higher (P < 0.01) than the VO2 expected at this P, calculated from the linear relationship between VO2 and P derived from the data collected below LT. This fall in locomotory efficiency expressed by the additional increase in VO2, amounting to 572 (SD 269) ml O2 x min(-1), was accompanied by a significant increase in [La-]pl amounting to 7.04 (SD 2.2) mmol x l(-1), a significant increase in blood hydrogen ion concentration ([H+]b) to 7.4 (SD 3) nmol x l(-1) and a significant fall in blood bicarbonate concentration to 5.78 (SD 1.7) mmol x l(-1), in relation to the values measured at the P of the LT. We also correlated the individual values of the additional VO2 with the increases (delta) in variables [La-]pl and delta[H+]b. The delta values for [La-]pl and delta[H+]b were expressed as the differences between values reached at the Pmax,obs at VO2max and the values at LT. No significant correlations between the additional VO2 and delta[La-]pl on [H+]b were found. In conclusion, when performing an incremental exercise test, exceeding P corresponding to LT was accompanied by a significant additional increase in VO2 above that expected from the linear relationship between VO2 and P occurring at lower P. However, the magnitude of the additional increase in VO2 did not correlate with the magnitude of the increases in [La-]pl and [H+]b reached in the final stages of the incremental test.

Authors+Show Affiliations

Department of Physiology and Biochemistry, AWF-Krakow, Cracow, Poland.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

9562296

Citation

Zoladz, J A., et al. "Oxygen Uptake Does Not Increase Linearly at High Power Outputs During Incremental Exercise Test in Humans." European Journal of Applied Physiology and Occupational Physiology, vol. 77, no. 5, 1998, pp. 445-51.
Zoladz JA, Duda K, Majerczak J. Oxygen uptake does not increase linearly at high power outputs during incremental exercise test in humans. Eur J Appl Physiol Occup Physiol. 1998;77(5):445-51.
Zoladz, J. A., Duda, K., & Majerczak, J. (1998). Oxygen uptake does not increase linearly at high power outputs during incremental exercise test in humans. European Journal of Applied Physiology and Occupational Physiology, 77(5), 445-51.
Zoladz JA, Duda K, Majerczak J. Oxygen Uptake Does Not Increase Linearly at High Power Outputs During Incremental Exercise Test in Humans. Eur J Appl Physiol Occup Physiol. 1998;77(5):445-51. PubMed PMID: 9562296.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oxygen uptake does not increase linearly at high power outputs during incremental exercise test in humans. AU - Zoladz,J A, AU - Duda,K, AU - Majerczak,J, PY - 1998/4/30/pubmed PY - 1998/4/30/medline PY - 1998/4/30/entrez SP - 445 EP - 51 JF - European journal of applied physiology and occupational physiology JO - Eur J Appl Physiol Occup Physiol VL - 77 IS - 5 N2 - A group of 12 healthy non-smoking men [mean age 22.3 (SD 1.1) years], performed an incremental exercise test. The test started at 30 W, followed by increases in power output (P) of 30 W every 3 min, until exhaustion. Blood samples were taken from an antecubital vein for determination of plasma concentration lactate [La-]pl and acid-base balance variables. Below the lactate threshold (LT) defined in this study as the highest P above which a sustained increase in [La-]pl was observed (at least 0.5 mmol x l[-1] within 3 min), the pulmonary oxygen uptake (VO2) measured breath-by-breath, showed a linear relationship with P. However, at P above LT [in this study 135 (SD 30) W] there was an additional accumulating increase in VO2 above that expected from the increase in P alone. The magnitude of this effect was illustrated by the difference in the final P observed at maximal oxygen uptake (VO2max) during the incremental exercise test (Pmax,obs at VO2max) and the expected power output at VO2max(Pmax,exp at VO2max) predicted from the linear VO2-P relationship derived from the data collected below LT. The Pmax,obs at VO2max amounting to 270 (SD 19) W was 65.1 (SD 35) W (19%) lower (P < 0.01) than the Pmax,exp at VO2max. The mean value of VO2max reached at Pmax,obs amounted to 3555 (SD 226) ml x min(-1) which was 572 (SD 269) ml x min(-1) higher (P < 0.01) than the VO2 expected at this P, calculated from the linear relationship between VO2 and P derived from the data collected below LT. This fall in locomotory efficiency expressed by the additional increase in VO2, amounting to 572 (SD 269) ml O2 x min(-1), was accompanied by a significant increase in [La-]pl amounting to 7.04 (SD 2.2) mmol x l(-1), a significant increase in blood hydrogen ion concentration ([H+]b) to 7.4 (SD 3) nmol x l(-1) and a significant fall in blood bicarbonate concentration to 5.78 (SD 1.7) mmol x l(-1), in relation to the values measured at the P of the LT. We also correlated the individual values of the additional VO2 with the increases (delta) in variables [La-]pl and delta[H+]b. The delta values for [La-]pl and delta[H+]b were expressed as the differences between values reached at the Pmax,obs at VO2max and the values at LT. No significant correlations between the additional VO2 and delta[La-]pl on [H+]b were found. In conclusion, when performing an incremental exercise test, exceeding P corresponding to LT was accompanied by a significant additional increase in VO2 above that expected from the linear relationship between VO2 and P occurring at lower P. However, the magnitude of the additional increase in VO2 did not correlate with the magnitude of the increases in [La-]pl and [H+]b reached in the final stages of the incremental test. SN - 0301-5548 UR - https://www.unboundmedicine.com/medline/citation/9562296/Oxygen_uptake_does_not_increase_linearly_at_high_power_outputs_during_incremental_exercise_test_in_humans_ L2 - https://medlineplus.gov/exerciseandphysicalfitness.html DB - PRIME DP - Unbound Medicine ER -