Increased cardiac output elicits higher VO2max in response to self-paced exercise

Todd Anthony Astorino, David William McMillan, Ross Montgomery Edmunds, Eduardo Sanchez

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Recently, a self-paced protocol demonstrated higher maximal oxygen uptake versus the traditional ramp protocol. The primary aim of the current study was to further explore potential differences in maximal oxygen uptake between the ramp and self-paced protocols using simultaneous measurement of cardiac output. Active men and women of various fitness levels (N= 30, mean age = 26.0 ± 5.0 years) completed 3 graded exercise tests separated by aminimumof 48 h. Participants initially completed progressive ramp exercise to exhaustion to determine maximal oxygen uptake followed by a verification test to confirm maximal oxygen uptake attainment. Over the next 2 sessions, they performed a self-paced and an additional ramp protocol. During exercise, gas exchange data were obtained using indirect calorimetry, and thoracic impedance was utilized to estimate hemodynamic function (stroke volume and cardiac output). One-way ANOVA with repeated measures was used to determine differences in maximal oxygen uptake and cardiac output between ramp and self-paced testing. Results demonstrated lower (p < 0.001) maximal oxygen uptake via the ramp (47.2 ± 10.2 mL·kg–1·min–1) versus the self-paced (50.2 ± 9.6 mL·kg–1·min–1) protocol, with no interaction (p = 0.06) seen for fitness level. Maximal heart rate and cardiac output (p = 0.02) were higher in the self-paced protocol versus ramp exercise. In conclusion, data show that the traditional ramp protocol may underestimate maximal oxygen uptake compared with a newly developed self-paced protocol, with a greater cardiac output potentially responsible for this outcome.

Original languageEnglish (US)
Pages (from-to)223-229
Number of pages7
JournalApplied Physiology, Nutrition and Metabolism
Issue number3
StatePublished - Nov 20 2015
Externally publishedYes


  • Cycle ergometer
  • Maximal oxygen uptake
  • RPE
  • Stroke volume
  • V˙ O2max limitations

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Nutrition and Dietetics
  • Physiology (medical)


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