title: Local and systemic effects of leg cycling training on arterial wall thickness in healthy humans.
abstract: Exercise training is associated with direct effects on conduit artery function and structure. Cross-sectional studies suggest the presence of systemic changes in wall thickness as a result of exercise in healthy subjects, but no previous study has examined this question in humans undertaking exercise training.
  
  
  OBJECTIVE
  To examine the change in superficial femoral (SFA, i.e. local effect) and carotid (CA, i.e. systemic effect) artery wall thickness across 8 weeks of lower limb cycle training in healthy young men.
  
  
  METHODS
  Fourteen healthy young male subjects were assigned to an 8-week training study of cycling exercise (n = 9) or a control period (n = 5). Before, during (2, 4 and 6 weeks) and after training, SFA and CA wall thickness was examined using automated edge-detection of high resolution ultrasound images. We also measured resting diameter and calculated the wall:lumen(W:L)-ratio.
  
  
  RESULTS
  Exercise training did not alter CA or SFA baseline diameter (P = 0.14), but was associated with gradual, consistent and significant decreases in wall thickness and W:L-ratio in both the CA and SFA (P < 0.001 and 0.002, respectively). Two-way ANOVA revealed a comparable magnitude of decrease in wall thickness and W:L-ratio in both arteries across the 8-week period (interaction-effect; P = 0.29 and 0.12, respectively). No changes in artery diameter, wall thickness or W:L-ratio were apparent in controls (0.82, 0.38 and 0.52, respectively).
  
  
  CONCLUSIONS
  We found that cycle exercise training in healthy young individuals is associated with modest, but significant, decreases in wall thickness in the superficial femoral and carotid arteries. These findings suggest that exercise training causes systemic adaptation of the arterial wall in healthy young subjects.
authors.affiliation: Research Institute for Sport and Exercise Science, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool L3 3AF, United Kingdom. D.Thijssen@ljmu.ac.uk
authors.forename: Dick H J
authors.initials: DH
authors.lastname: Thijssen
authors.forename: Ellen A
authors.initials: EA
authors.lastname: Dawson
authors.forename: Inge C L
authors.initials: IC
authors.lastname: van den Munckhof
authors.forename: Gurpreet K
authors.initials: GK
authors.lastname: Birk
authors.forename: N
authors.initials: N
authors.lastname: Timothy Cable
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Green
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D001158:Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D001642:Bicycling / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000517:prevention & control; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000502:physiology*; D059168:Carotid Intima-Media Thickness; D015444:Exercise / Q000502:physiology; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000502:physiology; D006801:Humans; D007866:Leg / Q000098:blood supply* / Q000502:physiology*; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D012016:Reference Values; D012307:Risk Factors; D055815:Young Adult
keywords: Cardiovascular risk; Exercise training; Intima-media thickness; Ultrasound