Reference Values for Peak Exercise Cardiac Output in Healthy Individuals.

Area of Science:

• Cardiology
• Exercise Physiology
• Pulmonary Medicine

Background:

• Cardiac output (Q˙) is vital for assessing cardiac function and managing heart diseases.
• Historically, peak exercise Q˙ measurement required invasive methods, limiting large-scale studies.
• Noninvasive techniques like inert gas rebreathing (IGR) now enable accurate peak exercise Q˙ determination.

Purpose of the Study:

• Establish reference values for peak Q˙ in a healthy general population.
• Develop a formula to estimate peak exercise Q˙ using peak oxygen uptake (V˙o₂).

Main Methods:

• Studied 500 healthy subjects (18-77 years) using maximal cardiopulmonary exercise testing.
• Measured peak Q˙ noninvasively with the inert gas rebreathing (IGR) technique.
• Collected data on peak oxygen uptake (V˙o₂) for formula development.

Main Results:

• Peak Q˙ averaged 13.2 ± 3.5 L/min overall, with significant differences between men (15.3 L/min) and women (11.0 L/min).
• Peak V˙o₂ and Q˙ showed a progressive decrease with advancing age.
• Developed predictive formulas for peak Q˙ based on peak V˙o₂: (4.4 × peak V˙o₂) + 4.3 (overall), (4.3 × peak V˙o₂) + 4.5 (men), and (4.9 × peak V˙o₂) + 3.6 (women).

Conclusions:

• Simultaneous noninvasive measurement of Q˙ and V˙o₂ at peak exercise in a large cohort allows for prediction.
• The derived equation provides a reliable method to estimate peak exercise Q˙ from peak V˙o₂.
• This facilitates noninvasive assessment of cardiac function during exercise in clinical and research settings.