Open AccessRapid onset vasodilation with single muscle contractions in the leg: influence of age
Author(s) -
Hughes William E.,
Ueda Kenichi,
Treichler David P.,
Casey Darren P.
Publication year - 2015
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.12516
Subject(s) - vasodilation , medicine , forearm , cardiology , ageing , femoral artery , contraction (grammar) , muscle contraction , skeletal muscle , brachial artery , blood flow , blood pressure , anatomy
Abstract The influence of aging on contraction‐induced rapid vasodilation has been well characterized in the forearm. We sought to examine the impact of aging on contraction‐induced rapid vasodilation in the leg following single muscle contractions and determine whether potential age‐related impairments were similar between limbs (leg vs. arm). Fourteen young (23 ± 1 years) and 16 older (66 ± 1 years) adults performed single leg knee extensions at 20%, 40%, and 60% of work rate maximum. Femoral artery diameter and blood velocity were measured using Doppler ultrasound. Limb vascular conductance ( VC ) was calculated using blood flow ( mL ·min −1 ) and mean arterial pressure (mmHg). Peak and total vasodilator responses in the leg (change [Δ] in VC from baseline) were blunted in older adults by 44–50% across exercise intensities ( P < 0.05 for all). When normalized for muscle mass, age‐related differences were still evident ( P < 0.05). Comparing the rapid vasodilator responses between the arm and the leg of the same individuals at similar relative intensities (20% and 40%) reveals that aging influences peak and total vasodilation equally between the limbs (no significant age × limb interaction at either intensity, P = 0.28–0.80). Our data demonstrate that (1) older adults exhibit an attenuated rapid hyperemic and vasodilator response in the leg; and (2) the age‐related reductions in rapid vasodilation are similar between the arm and the leg. The mechanisms contributing to the age‐related differences in contraction‐induced rapid vasodilation are perhaps similar to those seen with the forearm model, but have not been confirmed.