Effects of changes in large arterial compliance and small arterial buffer function with resistance training on cerebral blood flow pulsatility

BACKGROUND: Cerebral blood flow (CBF) pulsatility is dampened by large and small arterial buffer functions. Resistance training (RT) improved small arterial buffer function regardless of impaired large arterial compliance. This response to small arterial buffer function with RT may be compensatory adaptation to impaired large arterial compliance for protecting end-organs such as the brain from excessive pulsatile stresses. This study aimed to investigate the effects of changes in large arterial compliance and small arterial buffer functions with RT on CBF pulsatility. METHODS: Twenty healthy men were assigned to either the RT group (N.=10) or the control (CON) group (N.=10). Subjects in the RT group exercised three times/week for 8 weeks. Arterial compliance of common carotid artery was measured as an index of large arterial compliance. Dampening factor (DF) in the cerebral artery and pulsatility index (PI) in the middle cerebral artery (MCA) were used to evaluate small arterial buffer function and CBF pulsatility, respectively. RESULTS: In the RT group, arterial compliance significantly decreased (P<0.05) and DF in the cerebral artery significantly increased (P<0.05) after intervention compared to baseline. However, there was no change in PI in MCA in both groups. A negative correlation was found between ∆ arterial compliance and ∆ DF in the cerebral artery (r=-0.671, P<0.05). CONCLUSIONS: These results may suggest that the response of small arteries to RT is a compensatory adaptation to impaired large arterial compliance for protecting end organs from excessive pulsatile stresses.