Aortic Stiffness Increased in Spinal Cord Injury When Matched for Physical Activity

PURPOSE: The objective of this study is to compare arterial stiffness between those with spinal cord injury (SCI) and able-bodied (AB) individuals when matched for habitual level of physical activity. METHODS: A total of 17 SCI and 17 AB individuals were matched for sex, age, weight, blood pressure, and levels of self-reported habitual physical activity (Godin-Shephard). Measures included central pulse wave velocity (PWV) (carotid-femoral PWV (cfPWV)) and lower limb PWV (femoral--toe PWV(ftPWV)) as well as large and small arterial compliance. RESULTS: The cfPWV was significantly elevated (7.3 ± 2.1 vs. 5.7 ± 1.4 m·s, P < 0.05) in SCI compared with AB. No other measures of arterial stiffness were different between the groups. Moderate to vigorous physical activity was significantly correlated with both large (r = 0.48, P < 0.05) and small (r = 0.65, P < 0.01) artery compliance, but not cfPWV or ftPWV. CONCLUSIONS: Both large and small artery compliance appear to be associated with habitual physical activity in physically active individuals with SCI. However, we did not show that physical activity is associated with PWV in physically active individuals with SCI. These findings suggest that factors other than physical inactivity may mediate the increase in arterial stiffness widely reported in the SCI population.