title: Exercise training augments regional bone and marrow blood flow during exercise.
abstract: BACKGROUND
  The principal nutrient artery to the femur demonstrates an increase in nitric oxide-mediated vasodilation in rats after treadmill exercise training. The present study sought to determine whether exercise training improves hindlimb bone and marrow blood flow distribution at rest and during exercise.
  
  
  METHODS
  Six 8-month old male Sprague-Dawley rats were exercise trained (ET) with treadmill walking at 15 m · min(-1) up a 15° incline for 60 min · d(-1) over a 10- to 12-wk period. Sedentary (SED) control animals were acclimated to treadmill exercise for 5 min · d(-1) during the week preceding the blood flow measurements. Blood flow to nine distinct regions of the femur, tibia, and fibula was determined at rest and during low-intensity exercise (15 m · min(-1) walking, 0° incline) using the reference sample microsphere method.
  
  
  RESULTS
  The results demonstrate an augmentation of exercise hyperemia above that observed in SED rats during exercise in only one region of the bone, the femoral diaphysis, of ET rats. However, whereas exercise hyperemia occurred in three of the nine hindlimb bone regions measured in SED rats, exercise hyperemia occurred in seven of nine regions in ET rats.
  
  
  CONCLUSIONS
  These data indicate an increase in generalized hindlimb bone and marrow blood flow during physical activity after a period of exercise training. Elevations in regional bone and marrow blood flow after training may augment medullary pressure and bone interstitial fluid flow, thus benefiting bone integrity.
authors.affiliation: 1Center for Exercise Science, Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL; and 2Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL.
authors.forename: John N
authors.initials: JN
authors.lastname: Stabley
authors.forename: Natasha C
authors.initials: NC
authors.lastname: Moningka
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Behnke
authors.forename: Michael D
authors.initials: MD
authors.lastname: Delp
mesh_terms: D000818:Animals; D015992:Body Mass Index; D001853:Bone Marrow / Q000098:blood supply*; D005269:Femur / Q000098:blood supply*; D005360:Fibula / Q000098:blood supply*; D006439:Hemodynamics; D006614:Hindlimb / Q000098:blood supply; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow; D013977:Tibia / Q000098:blood supply*; D014664:Vasodilation