title: Increases in blood flow and shear stress to nonworking limbs during incremental exercise.
abstract: OBJECTIVE
  Regular exercise augments endothelium-dependent vasodilatory capacity in the vasculature located in the nonworking limbs. We determined whether blood flow as well as shear stress would change in inactive limbs during acute incremental exercise.
  
  
  METHODS
  Eight young healthy female subjects performed graded exercise on arm and leg cycle ergometers that had been modified to minimize the movement of nonworking limbs and to facilitate the placement of Doppler transducers. Both brachial and femoral blood flow was monitored using Doppler ultrasonography. EMG activity was also measured to document that there was no muscular activity in nonworking muscles.
  
  
  RESULTS
  During leg exercise, brachial blood flow and calculated shear stress gradually and curvilinearly increased (P < 0.05). At the peak work rate, there was an approximately fourfold increase in blood flow in the brachial artery (19 +/- 6 vs 77 +/- 16 mL x min(-1)). Femoral blood flow and calculated shear stress increased progressively and linearly during arm exercise (P < 0.05).
  
  
  CONCLUSIONS
  We concluded that blood flow to the nonworking limbs increases markedly in proportion to the work intensity. These results suggest that the conduit arteries in the nonworking limbs are exposed to increases in blood flow and shear stress during exercise.
authors.affiliation: Research Institute of Physical Fitness, Japan Women's College of Physical Education, Setagaya, Tokyo, Japan. htanaka@mail.utexas.edu
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Shizuyo
authors.initials: S
authors.lastname: Shimizu
authors.forename: Fumiko
authors.initials: F
authors.lastname: Ohmori
authors.forename: Yoshiho
authors.initials: Y
authors.lastname: Muraoka
authors.forename: Mana
authors.initials: M
authors.lastname: Kumagai
authors.forename: Mutsuko
authors.initials: M
authors.lastname: Yoshizawa
authors.forename: Atsuko
authors.initials: A
authors.lastname: Kagaya
mesh_terms: D000328:Adult; D001132:Arm / Q000098:blood supply* / Q000000981:diagnostic imaging; D001642:Bicycling; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007564:Japan; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D013314:Stress, Mechanical; D014463:Ultrasonography; D014664:Vasodilation