Effects of training resumption on conduit arterial diameter in elite rowers.
BACKGROUND
Exercise training is a known stimulus for arteriogenesis, but it is unclear whether elite athletes, who exhibit increased conduit vessel diameter at rest, experience further structural vascular adaptations as a result of intense exercise training.


METHODS
Cross-sectional comparisons were performed between elite rowers (N = 17), following a respite from training, and eight untrained age- and gender-matched controls to assess the effects of long-term exercise on vessel structure. To determine the impact of the resumption of intensive exercise training on conduit artery structure, measures were repeated following 3 and 6 months of training in the athletes; the controls remained inactive. Conduit vessel structure was assessed, using high-resolution B-mode ultrasound, as brachial artery diameter at rest (BADr) and in response to 5-min (BAD5) and 10-min (BAD10) periods of forearm cuff ischemia. Shear rate profiles were also analyzed following cuff deflation at all time points.


RESULTS
At entry, all measures of BAD were greater (all P < 0.05) in the athletes relative to controls (athletes vs controls; BADr 4.47 +/- 0.10 vs 3.84 +/- 0.22 mm; BAD5 4.70 +/- 0.10 vs 4.05 +/- 0.36 mm, and BAD10 4.93 +/- 0.10 vs 4.07 +/- 0.25 mm). Resumption of exercise training caused a further increase in brachial artery diameters in the athletes at 3 months (BADr, 4.71 +/- 0.10 mm, P < 0.01; BAD5 4.94 +/- 0.10 mm, P < 0.05; BAD10 5.12 +/- 0.10 mm, P < 0.001), which were maintained, but not further increased, after 6 months of training.


CONCLUSIONS
Athletes exhibit enhanced conduit artery diameters at rest and in response to vasodilator stimuli. Despite this long-term training effect on arterial structure, resumption of training further enhances diameter, an effect that occurs within 3 months.
Naylor
Louise H
LH
School of Human Movement and Exercise Science, University of Western Australia, Nedlands, Australia.
O'Driscoll
Gerard
G
Fitzsimons
Martin
M
Arnolda
Leonard F
LF
Green
Daniel J
DJ
D000328:Adult; D001916:Brachial Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D003430:Cross-Sectional Studies; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D013177:Sports; D014463:Ultrasonography; D014664:Vasodilation; D014904:Western Australia