The VO(2)-on kinetics in constant load exercise sub-anaerobic threshold reflects endothelial function and dysfunction...

Area of Science:

• Cardiovascular Physiology
• Exercise Physiology
• Clinical Diagnostics

Background:

• Endothelial dysfunction is a key factor in cardiovascular diseases.
• Current methods for evaluating endothelial function can be invasive or indirect.
• A non-invasive, sensitive marker for endothelial function is needed.

Purpose of the Study:

• To propose and validate a novel test for assessing endothelial function.
• To utilize oxygen consumption (VO2) on-transition kinetics below the anaerobic threshold (AT) as a measure.
• To evaluate endothelial dysfunction in healthy individuals and patients with ischemic-hypertensive cardiopathy.

Main Methods:

• Two cardiopulmonary exercise tests were conducted on a cycle ergometer.
• Subjects performed a pre-test followed by a 6-minute constant load exercise at 90% AT.
• Net phase 3 VO2 on-kinetics and phase 2 time constant (tau) were measured to assess endothelial dysfunction.

Main Results:

• Shorter tau values were observed in repeated tests and with shorter intervals between tests.
• In heart patients, a lower exercise intensity (70% AT vs. 80% AT) significantly shortened tau.
• NYHA class in heart patients strongly correlated with tau duration, unlike ejection fraction (EF).
• Pharmacological interventions (Doxazosin, Tadalafil) significantly reduced tau.

Conclusions:

• VO2 on-transition kinetics during sub-anaerobic threshold exercise are highly sensitive to endothelial function.
• This method provides a valuable, non-invasive marker for evaluating endothelial dysfunction in muscular microcirculation.
• The test holds potential for clinical application in diagnosing and monitoring cardiovascular health.