Arterial dilator function in athletes: present and future perspectives

Although it is well established that exercise training conditions the vasculature (Joyner and Green, 2009), the status of arterial function in long-term trained subjects (i.e., athletes, ATH) has been recently disputed (Green, 2013; Montero et al., 2013). The controversy arose as to whether vasodilator function was enhanced in ATH compared with untrained healthy peers (Green et al., 2013). This contention was justified by the conflicting report of decreased (Green et al., 2011; Phillips et al., 2011) and normal (Franzoni et al., 2005b; Moe et al., 2005; Naylor et al., 2006; Ballard et al., 2008; Rognmo et al., 2008; Nualnim et al., 2011; Phillips et al., 2011; Rowley et al., 2012; Agrotou et al., 2013; Green et al., 2013) but also increased (Jensen-Urstad et al., 1999; Rywik et al., 1999; Rinder et al., 2000; Franzoni et al., 2005b; Kasikcioglu et al., 2005; Rickenlund et al., 2005; Tanriverdi et al., 2005; Galetta et al., 2006; Hagmar et al., 2006; Walther et al., 2008; Florescu et al., 2010; Nualnim et al., 2011; Welsch et al., 2013) flow-mediated dilation (FMD), a common index of conduit artery dilator function, in ATH vs. age-matched controls. Likewise, the evidence on resistance artery dilator function was apparently heterogeneous (Green et al., 2012). Presumably, differences in methodology, study population and the small sample size of previous reports, among others, may have contributed to cloud the status of arterial function in ATH, leading to wide speculation (Green, 2013; Montero et al., 2013). What follows is a brief viewpoint on the state-of-the-art including comprehensive meta-analytic data spanning through macroand microvascular dilator function in primarily endurance-trained ATH, as well as an insight in to next challenges to the field.