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MAIONE D, CICERO AFG, BACCHELLI S, COSENTINO ER, DEGLI ESPOSTI D, MANNERS DN, RINALDI ER, ROSTICCI M, SENALDI R, AMBROSIONI E, BORGHI C. The VO2-on Kinetics in Constant Load Exercise Sub-Anaerobic Threshold Reflects Endothelial Function and Dysfunction in Muscle Microcirculation. Physiol Res 2015; 64:807-19. [DOI: 10.33549/physiolres.932833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
To propose a test to evaluate endothelial function, based on VO2 on-transition kinetics in sub-anaerobic threshold (AT) constant load exercise, we tested healthy subjects and patients with ischemic-hypertensive cardiopathy by two cardiopulmonary tests on a cycle ergometer endowed with an electric motor to overcome initial inertia: a pre-test and, after at least 24 h, one 6 min constant load exercise at 90 % AT. We measured net phase 3 VO2-on kinetics and, by phase 2 time constant (τ), valued endothelial dysfunction. We found shorter τ in repeated tests, shorter time between first and second test, by persisting endothelium-dependent arteriolar vasodilatation and/or several other mechanisms. Reducing load to 80 % and 90 % AT did not produce significant changes in τ of healthy volunteers, while in heart patients an AT load of 70 %, compared to 80 % AT, shortened τ (=4.38±1.65 s, p=0.013). In heart patients, no correlation was found between NYHA class, ejection fraction (EF), and the two variables derived from incremental cycle cardio-pulmonary exercise, as well as between EF and τ; while NYHA class groups were well correlated with τ duration (r=0.92, p=0.0001). Doxazosin and tadalafil also significantly reduced τ. In conclusion, the O2 consumption kinetics during the on-transition of constant load exercise below the anaerobic threshold are highly sensitive to endothelial function in muscular microcirculation, and constitute a marker for the evaluation of endothelial dysfunction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - C. BORGHI
- Department of Medicine and Surgery Sciences, University of Bologna, Italy
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