Related Experiment Video
Updated: Aug 7, 2026
Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine
Published on: February 9, 2016
Non-linear relationships between central cardiovascular variables and VO2 during incremental cycling exercise in
1Exercise Physiology Laboratories, The University of New Mexico, Albuquerque, NM, USA. cvella@utep.edu
Aim:
The purpose of this study was to examine the relationships between the central cardiovascular variables (cardiac output, stroke volume and heart rate) and oxygen uptake (VO2) during continuous, incremental cycle exercise to maximal aerobic capacity (VO2max).
Methods:
Twenty-one moderately to highly trained males (n=19) and females (n=2) participated in the study. A baseline maximal exercise test was performed to measure VO2max. Following the initial VO2max test, cardiac output was measured (CO2 rebreathing technique) at rest and 3 times during each of 4 exercise trials (2 submaximal tests to 90% VO2max and 2 maximal tests). Stroke volume and arteriovenous O2 difference were calculated using standard equations.
Results:
Significant non-linear relationships were found between all central cardiovascular variables and VO2 (P<0.01). A plateau in cardiac output at VO2max was identified in 3 subjects. Stroke volume plateaued at an average of 37+/-12.5% of VO2max in 18 subjects and increased continuously to VO2max in 3 subjects. The arteriovenous O2 difference progressively increased to VO2max in 17 subjects and revealed a plateau response in 4 subjects.
Conclusions:
Our data suggest that there is a significant non-linear relationship between the central cardiovascular variables and VO2 during incremental exercise to VO2max. Furthermore, depending on the person, VO2max may be limited by cardiac output (evidence of cardiac output[Q] plateau) or peripheral factors (continued increase in Q).
More Related Videos
04:20Integration of Brain Tissue Saturation Monitoring in Cardiopulmonary Exercise Testing in Patients with Heart Failure
Published on: October 1, 2019
09:33Using Near-Infrared Spectroscopy Wearable Devices to Identify Central Versus Peripheral Limitations During Exercise
Published on: December 19, 2024
Related Concept Videos
01:30Factors Influencing Heart Rate
Let us explore the significant factors affecting heart rate, including age, body temperature, posture, acute pain, chemical influences,...
01:25Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
01:17Exercise and Cardiac Output
Sustained exercise increases the muscles' oxygen demand, which can be met...
01:20Exercise and Cardiovascular Response
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart rate...
01:22Cardiac Output II: Effect of Stroke Volume on Cardiac Output
Preload
Preload refers to the initial elongation of the cardiac myocytes before contraction and is related to the volume of blood filling the heart at the end of diastole, or end-diastolic volume. The...