Habitual Physical Activity Mitigates the Adverse Effects of Metabolic Syndrome on Arterial Stiffness and Cerebral White Matter Integrity

Abstract

PURPOSE: Metabolic syndrome (MetS) adversely affects the vasculature and cerebral white matter integrity. Arterial stiffening has been associated with diminished cerebral white matter integrity. Habitual physical activity (PA) can ameliorate components of MetS and subsequently affect arterial stiffening and white matter integrity. Our aim was to determine the role of habitual PA on mitigating the adverse influence of MetS on arterial stiffness and cerebral white matter integrity. METHODS: Sixty-six middle-aged adults (40-62 years) composed of 27 healthy, 18 sedentary MetS (Sed MetS), and 21 physically active MetS individuals (Active MetS) were studied. Carotid artery stiffness was assessed via simultaneous ultrasound and tonometry. Cerebral white matter integrity was measured using diffusion tensor imaging through metrics of fractional anisotropy (FA) and mean diffusivity (MD). RESULTS: Carotid β-stiffness index in Active MetS was lower than Sed MetS but was not different from Healthy controls (6.6±1.5, 7.7±2.1, and 5.6±1.6 au, p=0.001). The same group pattern was observed with white matter microstructural integrity in regions of interest (ROIs). Mean ROI FA was significantly greater in Active MetS compared with Sed MetS but was not different from Healthy controls (0.54±0.03, 0.51±0.02, and 0.53±0.02 au, p=0.012). Mean ROI MD was significantly lower in Active MetS compared with Sed MetS but was not different from Healthy controls (0.85±0.05, 0.89±0.05, and 0.86±0.05 mm2/s, p=0.019). CONCLUSION: Middle-aged individuals with MetS who habitually perform PA demonstrated lower arterial stiffness and more favorable cerebral white matter integrity than their sedentary peers, indicating that habitual exercise may be effective in mitigating the adverse effects of MetS on the vasculature and brain at midlife. This work was supported by grants from the NIH, NINDS (to APH) and the NSF (to AB).