Microvascular Dilator Function in Athletes: A Systematic Review and Meta-analysis.
OBJECTIVE
Despite the growing research interest in vascular adaptations to exercise training over the last few decades, it remains unclear whether microvascular function in healthy subjects can be further improved by regular training. Herein, we sought to systematically review the literature and determine whether microvascular dilator function is greater in athletes compared to age-matched healthy untrained subjects.


METHODS
We conducted a systematic search of MEDLINE, Cochrane, EMBASE, and Web of Science since their inceptions until October 2013 for articles evaluating indices of primarily microvascular endothelium-dependent or endothelium-independent dilation (MVEDD and MVEID, respectively) in athletes. A meta-analysis was performed to determine the standardized mean difference (SMD) in MVEDD and MVEID between athletes and age-matched controls. Subgroup analyses were used to study potential moderating factors.


RESULTS
Thirty-six studies were selected after systematic review, comprising 521 athletes (506 endurance-trained and 15 endurance- and strength-trained) and 496 age-matched control subjects. After data pooling, athletes presented higher MVEDD (31 studies; SMD, 0.47; P < 0.00001) and MVEID (14 studies; SMD, 0.51; P < 0.00001) compared with the control subjects. Similar results were observed in young (younger than 40 yr) and master (older than 55 yr) athletes when analyzed separately.


CONCLUSIONS
Both young and master athletes present enhanced microvascular function compared with age-matched untrained but otherwise healthy subjects. These data provide evidence of a positive association between exercise training and microvascular function in the absence of known underlying cardiovascular disease.
1Avignon University, Avignon, FRANCE; 2Department of Internal Medicine, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, THE NETHERLANDS; 3Applied Biology Department, Institute of Bioengineering, Miguel Hernandez University, SPAIN; 4School of Exercise Sciences, Australian Catholic University, Fitzroy, AUSTRALIA; 5School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, CANADA; 6Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO;7Department of Child Health, University of Missouri, Columbia, MO; 8Dalton Cardiovascular Research Center, University of Missouri, Columbia, MO.
David
D
Montero
Guillaume
G
Walther
Candela
C
Diaz-Cañestro
Kyra E
KE
Pyke
Jaume
J
Padilla
D056352:Athletes; D004730:Endothelium, Vascular / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008833:Microcirculation / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology*