Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

CO2 does not affect passive exercise ventilatory decline.

Harold J Bell1, James Duffin

  • 1Department of Physiology, University of Toronto, Toronto, Ontario, Canada M5S 1A8.

Journal of Applied Physiology (Bethesda, Md. : 1985)
|March 11, 2003
PubMed
Summary
This summary is machine-generated.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Apnea Testing for Brain Death/Death by Neurologic Criteria in Adults: A Prospective Multicenter Observational Study Assessing the Relationship Between Methodology, Safety, and Duration.

Critical care explorations·2026
Same author

Discordant ventilatory and efferent sympathetic responsiveness to peripheral and central chemoreflex stimulation in heart failure with reduced ejection fraction.

European journal of heart failure·2026
Same author

MRI-Based Classification of Cerebral Hemodynamic Failure With Resting Perfusion Metrics and Cerebrovascular Reactivity.

Stroke·2025
Same author

Cerebrovascular reactivity differences in healthy cerebral gray and white matter.

Magnetic resonance in medicine·2025
Same author

Excess ventilation and chemosensitivity in patients with inefficient ventilation and chronic coronary syndrome or heart failure: a case-control study.

Frontiers in physiology·2025
Same author

Cerebral perfusion metrics calculated directly from a hypoxia-induced step change in deoxyhemoglobin.

Scientific reports·2024
Same journal

Thoroughbred horses susceptible to Recurrent Exertional Rhabdomyolysis have elevated skeletal muscle mitochondrial capacities.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
Same journal

Change in Neutrophil-to-Lymphocyte Ratio after acute and chronic exercise: A Systematic Review and Meta-Analysis.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
Same journal

Ankylosing spondylitis and muscle sympathetic nerve activity: a case study.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
Same journal

Intracranial vasomotor and blood flow responses to light intensity aerobic exercise in young adults: a 4D flow MRI study.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
Same journal

Comparative assessments of the COSMED adaptive mixing chamber vs. breath-by-breath methods for oxygen uptake measurements in recreationally active adults.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
Same journal

Can we assess exercise metabolism from skin? Metabolomic profiles in skin dialysate collected during exercise.

Journal of applied physiology (Bethesda, Md. : 1985)·2026
See all related articles

Ventilation declines during passive exercise due to limb afferent feedback adaptation, not changes in carbon dioxide levels. This finding clarifies the mechanisms regulating breathing during physical activity.

Area of Science:

  • Exercise Physiology
  • Respiratory Physiology
  • Human Physiology

Background:

  • Breathing initially increases during passive exercise, then declines to a steady state.
  • This decline is hypothesized to result from reduced arterial CO2 or adapted afferent feedback.
  • The relative contribution of these factors remains unclear.

Purpose of the Study:

  • To investigate the mechanisms behind the decline in ventilation during passive exercise.
  • To differentiate the roles of arterial CO2 levels and afferent feedback adaptation.

Main Methods:

  • Compared ventilatory responses in 10 subjects during passive leg extension.
  • Utilized isocapnic (stable CO2) and poikilocapnic (variable CO2) conditions.
  • Measured ventilation changes at exercise onset and offset to assess afferent feedback drive.

Related Experiment Videos

Main Results:

  • End-tidal PCO2 decreased during poikilocapnic but not isocapnic exercise.
  • Ventilatory responses were similar in both isocapnic and poikilocapnic conditions.
  • A significant 68% decline in the drive to breathe from afferent feedback was observed.

Conclusions:

  • The decline in ventilation during passive exercise is primarily caused by adaptation in afferent feedback from moving limbs.
  • Reduced arterial CO2 levels do not significantly contribute to this ventilatory decline.