Habitual exercise training in older adults offsets the age-related prolongation in leg vasodilator kinetics during single-limb lower body exercise. J Appl Physiol (1985) 2018 Sep 01;125(3):746-754
Date
06/02/2018Pubmed ID
29856264Pubmed Central ID
PMC6842877DOI
10.1152/japplphysiol.00235.2018Scopus ID
2-s2.0-85053844349 (requires institutional sign-in at Scopus site) 3 CitationsAbstract
We tested the hypothesis that aging is associated with prolonged leg vasodilator kinetics and habitual exercise training in older adults improves these responses relative to untrained older adults. Additionally, we examined the relationship between contraction-induced rapid onset vasodilation (ROV) and vasodilator kinetics. Young ( n = 10), older untrained ( n = 13), and older trained ( n = 14) adults performed single and rhythmic knee-extension contractions at 20% and 40% work-rate maximum (WRmax). Femoral artery diameter and mean blood velocity were measured by Doppler ultrasound. Vascular conductance (VC; ml·min-1·mmHg-1) was calculated using blood flow (ml/min) and mean arterial pressure (mmHg). The primary outcome was the kinetic response (mean response time; MRT), modeled using an exponential model, expressed as the number of duty cycles to change 63% of the steady-state amplitude. There were no age- or training-related differences in VC MRT between the groups at 20% WRmax. Older untrained adults exhibited prolonged VC MRT at 40% WRmax relative to young (37 ± 16 vs. 24 ± 10 duty-cycles; P < 0.05) and older trained adults (37 ± 16 vs. 23 ± 14 duty-cycles; P < 0.05). There were no differences in VC MRT between young and older trained adults at 40% WRmax ( P = 0.96). There were no associations between peak ROV and VC MRT at 20% or 40% WRmax ( r = -0.08 and 0.22; P = 0.67 and 0.20, respectively) in the group as a whole. Our data suggest 1) advancing age prolongs leg vasodilator kinetics; 2) habitual exercise training in older adults offsets this age-related prolongation; and 3) contraction-induced ROV is not related to vasodilator kinetics within a group of young and older adults. NEW & NOTEWORTHY Aging is associated with reductions in exercise hyperemia and vasodilation at the onset of exercise, as well as during steady-state exercise. Habitual endurance exercise training offsets these age-related reductions. We found that aging prolongs vasodilator kinetics in the leg of older untrained but not older trained adults. Finally, our results demonstrate that contraction-induced rapid vasodilation is not associated with vasodilator kinetics within the leg of young and older adults.
Author List
Hughes WE, Kruse NT, Ueda K, Casey DPAuthor
William E. Hughes Postdoctoral Fellow in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdultAged
Aging
Anaerobic Threshold
Blood Pressure
Exercise
Female
Femoral Artery
Heart Rate
Humans
Kinetics
Leg
Lower Extremity
Male
Middle Aged
Muscle Contraction
Physical Conditioning, Human
Regional Blood Flow
Ultrasonography, Doppler
Vasodilation
Young Adult
