Vascular aging as measured by central arterial stiffness contributes to slow walking speed in older adults, but the impact of age-related changes in peripheral vascular function on walking performance is unclear. The aim of this study was to test the hypothesis that calf muscle-specific vasodilator responses are associated with walking performance fatigue in healthy older adults. Forty-five older (60-78. yrs) adults performed a fast-paced 400. m walk test. Twelve of these adults exhibited fatigue as defined by slowing of walking speed (≥. 0.02. m/s) measured during the first and last 100. m segments of the 400. m test. Peak calf vascular conductance was measured following 10. min of arterial occlusion using strain-gauge plethysmography. Superficial femoral artery (SFA) vascular conductance response to graded plantar-flexion exercise was measured using Doppler ultrasound. No difference was found for peak calf vascular conductance between adults that slowed walking speed and those that maintained walking speed (p > 0.05); however, older adults that slowed walking speed had a lower SFA vascular conductance response to calf exercise (at highest workload: slowed group, 2.4 ± 0.9 vs. maintained group, 3.6 ± 0.9. ml/kg/min/mm. Hg; p<. 0.01). Moreover, the initial increase in SFA vascular conductance from rest to exercise was positively correlated with the change in walking speed for all adults (rho = 0.41, p= 0.005). In conclusion, these results suggest that calf exercise hemodynamics are associated with walking performance fatigability in older adults.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology