title: Influence of chronic endurance exercise training on conduit artery retrograde and oscillatory shear in older adults.
abstract: OBJECTIVE
  With aging, there tends to be an increase in retrograde and oscillatory shear in peripheral conduit arteries of humans. Whether the increase in shear rate is due to the aging process or an effect of a less active lifestyle that often accompanies aging is unknown. Therefore, we examined whether chronic endurance exercise training attenuates conduit artery retrograde and oscillatory shear in older adults.
  
  
  METHODS
  Brachial and common femoral artery mean blood velocities and diameter were determined via Doppler ultrasound under resting conditions, and shear rate was calculated in 13 young (24 ± 2 years), 17 older untrained (66 ± 3 years), and 16 older endurance exercise-trained adults (66 ± 7 years).
  
  
  RESULTS
  Brachial artery retrograde (-9.1 ± 6.4 vs. -12.6 ± 9.4 s(-1); P = 0.35) and oscillatory (0.14 ± 0.08 vs. 0.14 ± 0.08 arbitrary units; P = 0.99) shear were similar between the older trained and untrained groups, whereas brachial artery retrograde and oscillatory shear were greater in older untrained compared to young adults (-5.0 ± 3.4, 0.08 ± 0.05 s(-1) arbitrary units, P = 0.017 and 0.048, respectively). There was no difference between the young and older trained brachial retrograde (P = 0.29) and oscillatory (P = 0.07) shear. Common femoral artery retrograde (-6.3 ± 2.9 s(-1)) and oscillatory (0.21 ± 0.08 arbitrary units) shear were reduced in older trained compared to the older untrained group (-10.4 ± 4.1 and 0.30 ± 0.09 s(-1) arbitrary units, both P = 0.005 and 0.006, respectively), yet similar to young adults (-7.1 ± 3.5 and 0.19 ± 0.06 s(-1) arbitrary units, P = 0.81 and 0.87, respectively).
  
  
  CONCLUSIONS
  Our results suggest that chronic endurance exercise training in older adults ameliorates retrograde and oscillatory shear rate patterns, particularly in the common femoral artery.
authors: Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA. darren-casey@uiowa.edu.|Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA. darren-casey@uiowa.edu.|Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA. darren-casey@uiowa.edu.
authors: Darren P
authors: DP
authors: Casey
authors: Department of Health and Human Physiology, University of Iowa, Iowa, IA, 52242, USA.
authors: Aaron C
authors: AC
authors: Schneider
authors: Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa, IA, 52242, USA.
authors: Kenichi
authors: K
authors: Ueda
mesh_terms: D000328:Adult; D000368:Aged; D001683:Biological Clocks / Q000502:physiology; D001783:Blood Flow Velocity; D001809:Blood Viscosity / Q000502:physiology*; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D064797:Physical Conditioning, Human / Q000379:methods* / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D033081:Shear Strength / Q000502:physiology; D018608:Ultrasonography, Doppler / Q000379:methods
keywords: Aging; Conduit artery; Exercise training; Shear rate