Author(s): NISHIWAKI, M., OI, N., KUME, D., Institution: OSAKA INSTITUTE OF TECHNOLOGY, Country: JAPAN, Abstract-ID: 2788

INTRODUCTION:
Numerous previous studies have shown that both acute and regular exercise reduce pulse wave velocity (PWV), an index of arterial stiffness. Increased arterial stiffness is an independent risk factor for future cardiovascular disease; therefore, preventing increases in arterial stiffness through exercise is of paramount importance. Reductions in arterial stiffness are generally thought to result from vascular structural changes, vascular functional changes, or a combination of both. Previous studies suggest that arterial stiffness responses to exercise are primarily influenced by increased blood flow and shear stress, indicating that vascular functional changes are induced by exercise. However, the effects of cycling exercise on arterial wall tissue elastic properties, as an index of vascular structural changes, remain largely unknown. Therefore, this study aimed to examine the effects of acute cycling exercise at different intensities on arterial wall tissue elastic properties.
METHODS:
Nineteen young men and women (21 ± 2 years) participated in four separate 40-min trials in random order on different days: (1) seated rest in a comfortable chair as a control (CON); (2) low-intensity exercise (LOW); (3) moderate-intensity exercise (MOD); and (4) severe-intensity exercise (SEV). Exercise intensity was prescribed based on heart rate levels of 100, 125, and 150 beats/min for LOW, MOD, and SEV, respectively. Carotid arterial wall tissue elastic properties during the diastolic phase were assessed using an ultrasound shear wave elastography system before (Pre), immediately after (Post 1), and 30 min after (Post 2) each trial. Arterial stiffness was also assessed by heart–ankle PWV.
RESULTS:
No significant differences in baseline parameters were observed among the trials. Carotid arterial wall tissue elastic properties did not significantly change after any trial (CON: 0.2 ± 5.8%; LOW: −1.1 ± 5.4%; MOD: 2.3 ± 6.5%; SEV: −0.6 ± 5.4%). In contrast, heart–ankle PWV was significantly reduced after the exercise trials (LOW, MOD, and SEV).
CONCLUSION:
These findings indicate that acute cycling exercise at different intensities does not significantly reduce carotid arterial wall tissue elastic properties. This suggests that acute exercise does not induce immediate vascular structural changes, and that the post-exercise reduction in arterial stiffness is likely attributable to functional rather than structural mechanisms.