Elucidating the Contribution of Aortic Impedance to Ventricular-Arterial Coupling During Exercise: An MRI-Based Study
【Supercategory：7. DESCENTE SPORTS SCIENCE Subcategory：7.47 Vol.47】
ABSTRACT
Because exercise alters both cardiac and vascular dynamics, the impact of aortic impedance on left ventricular ejection is likely to vary depending on the mode of exercise and an individual activity level. Aortic impedance, which represents the opposition to pulsatile blood flow, is a key determinant of left ventricular afterload and plays an important role in ventricular-arterial coupling. In this study, we aimed to investigate the influence of aortic impedance on left ventricular dynamics under two conditions: the acute effects of different exercise modes （Study 1） and the chronic adaptations observed in endurance-trained athletes（Study 2）， In Study 1, we assessed the relationship between aortic impedance and indices of left ventricular mechanical dynamic during rhythmic handgrip and dynamic cycling exercises. Handgrip exercise led to a selective increase in the pulsatile components of aortic impedance, particularly the characteristic impedance, which corresponds to aortic wall distensability. These changes were significantly associated with increases in myocardial oxygen demand and mechanical energy output of the left ventricle. In contrast, cycling exercise decreased aortic impedance across a wider frequency range, including both characteristic and lowfrequency harmonics. However, these changes showed no clear association with left ventricular mechanical dynamic indices, suggesting that different exercise modalities may influence ventricular-arterial interaction through distinct mechanisms. In Study 2, endurance-trained athletes exhibited chronically lower pulsatile aortic impedance at rest, which was associated with lower myocardial oxygen demand. However, no distinct features were found in mechanical energy indices. Together, these findings suggest that the effects of aortic impedance on ventricular-arterial coupling are modulated by both acute exercise mode and long-term exercise habits. Understanding these interactions may provide physiological insights for individualized exercise prescriptions aimed at optimizing cardiovascular efficiency.
DECENTE SPORTS SCIENCE Vol.47/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
Because exercise alters both cardiac and vascular dynamics, the impact of aortic impedance on left ventricular ejection is likely to vary depending on the mode of exercise and an individual activity level. Aortic impedance, which represents the opposition to pulsatile blood flow, is a key determinant of left ventricular afterload and plays an important role in ventricular-arterial coupling. In this study, we aimed to investigate the influence of aortic impedance on left ventricular dynamics under two conditions: the acute effects of different exercise modes （Study 1） and the chronic adaptations observed in endurance-trained athletes（Study 2）， In Study 1, we assessed the relationship between aortic impedance and indices of left ventricular mechanical dynamic during rhythmic handgrip and dynamic cycling exercises. Handgrip exercise led to a selective increase in the pulsatile components of aortic impedance, particularly the characteristic impedance, which corresponds to aortic wall distensability. These changes were significantly associated with increases in myocardial oxygen demand and mechanical energy output of the left ventricle. In contrast, cycling exercise decreased aortic impedance across a wider frequency range, including both characteristic and lowfrequency harmonics. However, these changes showed no clear association with left ventricular mechanical dynamic indices, suggesting that different exercise modalities may influence ventricular-arterial interaction through distinct mechanisms. In Study 2, endurance-trained athletes exhibited chronically lower pulsatile aortic impedance at rest, which was associated with lower myocardial oxygen demand. However, no distinct features were found in mechanical energy indices. Together, these findings suggest that the effects of aortic impedance on ventricular-arterial coupling are modulated by both acute exercise mode and long-term exercise habits. Understanding these interactions may provide physiological insights for individualized exercise prescriptions aimed at optimizing cardiovascular efficiency.
DECENTE SPORTS SCIENCE Vol.47/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
| Researcher | Marina Fukuie*1, Takashi Tarumi*1, Tsubasa Tomoto*1, Michinari Hieda*2 |
|---|---|
| University or institution | *1 Human Informatics and Interaction Research institute, National Institute of Advanced, *2 Department of Medicine and Biosystemic Science Hematology, Oncology, and Cardiovascular Medicine, School of Medicine Kyushu University Fukuoka Japan Industrial Science and Tehnology（AIST） |
Keywords
aortic input impedance, left ventricular-arterial coupling, left ventricular energetics, exercise modality, exercise measurement