Resistance Exercise, Carotid Artery Stiffness, and Cerebral Blood Flow Pulsatility

Lefferts, W., Augustine, J., Heffernan, K., Department of Exercise Science, Syracuse University, Syracuse, NY Cross-sectional studies have identified arterial stiffness as an important correlate of cerebral blood flow (CBF) pulsatility, an important predictor of cerebrovascular damage. Central artery stiffness increases acutely following a bout of resistance exercise (RE). It has yet to be elucidated whether RE-induced increases in arterial stiffness affect CBF pulsatility. Purpose: To investigate the effects of acute RE on carotid artery stiffness and CBF pulsatility. Methods: 18 healthy men (age 22 ± 1 yr; BMI 23.7 ± 0.5 kg∙m-2) underwent a) acute RE (5 sets, 5-RM bench press, 5 sets 10-RM bicep curls with 90 s rest intervals), and b) a time control condition (seated rest) in a randomized order. CBF pulsatility index (PI) was measured with transcranial Doppler at the middle cerebral artery (MCA). Common carotid artery (CCA) beta stiffness (β) and blood flow velocity PI were assessed using Doppler ultrasound. CCA pulse pressure was measured using applanation tonometry. Wave intensity analysis (WIA) was used to derive measures of forward (W1) and backward (Negative Area (NA)) travelling pressure waves to gain insight into origins of CBF pulsatility. Results: CCA β, and pulse pressure significantly increased post-RE (p \u3c 0.05). There was a significant increase in post-RE forward wave pressure (W1, p \u3c 0.05) with no changes in measures of backward/reflected wave pressure (lnNA, p \u3e 0.05). There were no changes in CCA PI or MCA PI following acute RE (p \u3e 0.05). Conclusions: Acute RE increases CCA stiffness and pressure pulsatility without affecting CCA or MCA flow pulsatility. Increases in pressure pulsatility are due to increases in forward wave pressure and not pressure from wave reflections