Physical Fitness Protects Against Age-Related Vascular Dysfunction in the Lower Limb

Abstract

Vascular function is reduced with sedentary aging, which contributes to increased cardiovascular disease risk with age. Physical activity can prevent, and/or reverse, age-related vascular dysfunction. Data supporting the beneficial impact of physical activity, however, are primarily derived from assessments of vascular function in the arm. PURPOSE: This study sought to examine the impact of aging and physical fitness on lower limb vascular function. METHODS: Flow-mediated dilation (FMD, Doppler ultrasound) of the superficial femoral and popliteal arteries (SFA and PA, respectively) was assessed in a total of 32 subjects, consisting of 8 young sedentary (Y; 23±1 yrs), 8 old sedentary (OS; 73±2 yrs), 8 old active (OA; 71±2 yrs), and 8 old endurance trained (OT; 72±1 yrs) adults. Subjects were grouped based upon age, physical activity (interview and accelerometry), and maximal oxygen consumption (VO2max) assessed on a cycle ergometer. RESULTS: FMD was reduced in the OS group relative to the Y in the SFA (Y: 4.3±0.9%, OS:1.7±0.4%, p<0.05) and PA (Y: 6.3±0.9% OS: 1.9±0.4%, p<0.05). Increasing levels of physical fitness corresponded to an increase in FMD in the SFA (OA: 2.9±0.6%, OT: 4.3±0.8%) and PA (OA: 2.3±0.8%, OT: 5.2±1.1%), such that SFA FMD was not different from the Y in the OA and OT groups, and PA FMD was not different from the Y in the OT group. Additionally, in the old subjects, both SFA (r=0.44) and PA (r=0.48) FMD were significantly correlated with VO2max. CONCLUSION: Collectively, these data suggest that physical fitness diminishes the detrimental effect of aging on lower limb vascular function. Importantly, these data extend observations in the arm, in terms of the benefits of physical activity on vascular function with advancing age, to the lower limb, which, as a consequence of limb-specific vascular aging, may be at a greater predisposition for age-related vascular dysfunction.