title: The Effect of Physical Activity on Passive Leg Movement-Induced Vasodilation with Age.
abstract: Because of reduced nitric oxide (NO) bioavailability with age, passive leg movement (PLM)-induced vasodilation is attenuated in older sedentary subjects and, unlike the young subjects, cannot be augmented by posture-induced elevations in femoral perfusion pressure. However, whether vasodilator function assessed with PLM, and therefore NO bioavailability, is preserved in older individuals with greater physical activity and fitness is unknown.
  
  
  
  PLM was performed on four subject groups: young sedentary (Y, 23 ± 1 yr, n = 12), old sedentary (OS, 73 ± 2 yr, n = 12), old active (OA, 71 ± 2 yr, n = 10), and old endurance trained (OT, 72 ± 1 yr, n = 10) in the supine and upright-seated posture. Hemodynamics were measured using ultrasound Doppler and finger photoplethysmography.
  
  
  
  In the supine posture, PLM-induced peak change in leg vascular conductance was significantly attenuated in the OS compared with the young subjects (OS = 4.9 ± 0.5, Y = 6.9 ± 0.7 mL·min·mm Hg) but was not different from the young in the OA and OT (OA = 5.9 ± 1.0, OT = 5.4 ± 0.4 mL·min·mm Hg). The upright-seated posture significantly augmented peak change in leg vascular conductance in all but the OS (OS = 4.9 ± 0.5, Y = 11.8 ± 1.3, OA = 7.3 ± 0.8, OT = 8.1 ± 0.8 mL·min·mm Hg), revealing a significant vasodilatory reserve capacity in the other groups (Y = 4.92 ± 1.18, OA = 1.37 ± 0.55, OT = 2.76 ± 0.95 mL·min·mm Hg).
  
  
  
  As PLM predominantly reflects NO-mediated vasodilation, these findings support the idea that augmenting physical activity and fitness can protect NO bioavailability, attenuating the deleterious effects of advancing age on vascular function.
authors.affiliation: 1Geriatric Research, Education, and Clinical Center Salt Lake City VAMC, UT; 2Department of Exercise and Sport Science University of Utah, Salt Lake City, UT; 3Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA; 4Department of Internal Medicine, University of Utah, Salt Lake City, UT; 5Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, NORWAY; 6Department of Physical Medicine and Rehabilitation, St. Olavs University Hospital, Trondheim, NORWAY; 7Hokksund Medical Rehabilitation Center, Hokksund, NORWAY; and 8Department of Sports and Outdoor Life Studies, Telemark University College, Bø, NORWAY.
authors.forename: H Jonathan
authors.initials: HJ
authors.lastname: Groot
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rossman
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Garten
authors.forename: Eivind
authors.initials: E
authors.lastname: Wang
authors.forename: Jan
authors.initials: J
authors.lastname: Hoff
authors.forename: Jan
authors.initials: J
authors.lastname: Helgerud
authors.forename: Russell S
authors.initials: RS
authors.lastname: Richardson
mesh_terms: D000367:Age Factors; D000368:Aged; D015444:Exercise; D005385:Fingers; D006439:Hemodynamics; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008297:Male; D009068:Movement; D009569:Nitric Oxide / Q000097:blood; D017156:Photoplethysmography; D011187:Posture; D012039:Regional Blood Flow; D057185:Sedentary Behavior; D018608:Ultrasonography, Doppler; D014664:Vasodilation; D055815:Young Adult
chemical_list: D009569:Nitric Oxide