Nine minutes of incremental arm-crank exercise increased superficial femoral artery flow-mediated dilation in able-bodied men (7.5% to 11.2%, P=0.03) but not in men with spinal cord injury (P=0.74).
Cross-Sectional (n=16)
Does a single bout of incremental arm-crank exercise improve superficial femoral artery endothelial function in men with spinal cord injury compared to able-bodied controls?
Acute upper limb exercise increases lower limb shear rate but fails to improve superficial femoral artery endothelial function in men with spinal cord injury, unlike in able-bodied controls.
Vascular improvements in the nonactive regions during exercise are likely primarily mediated by increased shear rate (SR). Individuals with spinal cord injury (SCI) experience sublesional vascular deconditioning and could potentially benefit from upper body exercise-induced increases in lower body SR. The present study utilized a single bout of incremental arm-crank exercise to generate exercise-induced SR changes in the superficial femoral artery in an effort to evaluate the acute postexercise impact on superficial femoral artery endothelial function via flow-mediated dilation (FMD), and determine regulatory factors in the nonactive legs of individuals with and without SCI. Eight individuals with SCI and eight age, sex, and waist-circumference-matched able-bodied (AB) controls participated. Nine minutes of incremental arm-crank exercise increased superficial femoral artery anterograde SR (P = 0.02 and P < 0.01), retrograde SR (P < 0.01 and P < 0.01), and oscillatory shear index (OSI) (P < 0.001 and P < 0.001) in both SCI and AB, respectively. However, these SR alterations resulted in acute postexercise increases in FMD in the AB group only (SCI 6.0 ± 1.2% to 6.3 ± 2.7%, P = 0.74; AB 7.5 ± 1.4% to 11.2 ± 1.4%, P = 0.03). While arm exercise has many cardiovascular benefits and results in changes in SR patterns in the nonactive legs, these changes are not sufficient to induce acute changes in FMD among individuals with SCI, and therefore are less likely to stimulate exercise training-associated improvements in nonactive limb endothelial function. Understanding the role of SR patterns on FMD brings us closer to designing effective strategies to combat impaired vascular function in both healthy and clinical populations.
Zepetnek et al. (Wed,) conducted a cross-sectional in Spinal cord injury (n=16). Incremental arm-crank exercise vs. Able-bodied controls was evaluated on Superficial femoral artery endothelial function via flow-mediated dilation (FMD). Nine minutes of incremental arm-crank exercise increased superficial femoral artery flow-mediated dilation in able-bodied men (7.5% to 11.2%, P=0.03) but not in men with spinal cord injury (P=0.74).