Effects of physical training of the dominant arm on ipsilateral radial artery distensibility and structure

Background Exercise training induces cardiovascular changes that are both g eneralized and restricted to the microcirculation of the tissues more activ ely involved in the exercise itself. Whether the local effect of exercise e xtends to larger arteries is unknown, however. Methods In the right and left upper limb of 17 right-handed subjects perfor ming an asymmetric training of the upper limbs (hammer throwers and basebal l players) and 16 age-matched sedentary controls, we continuously measured radial artery diameter, distensibility and wall thickness by an echotrackin g and a beat-to-beat finger blood pressure device, Arterial distensibility was calculated by the arctangent model of Langewouters and expressed as con tinuous values from diastolic to systolic blood pressure. Measurements were made: (1) in baseline conditions; (2) after release from prolonged proxima l ischaemia; and (3) after an increase in radial artery blood flow caused b y a short (4 min) distal ischaemia to determine the endothelial involvement in the training-induced change in arterial distensibility, Results In athletes the radial artery distensibility was markedly greater i n the right than in the left arm, the latter showing values slightly greate r than those seen in the two arms of sedentary subjects. In both arms and g roups radial artery distensibility increased markedly after prolonged ischa emia, the between arm and group differences being preserved, however. The r adial artery response to distal short ischaemia was, on the other hand, sim ilar in the two arms of the athletes, although greater in these subjects th an in the sedentary ones. Radial artery wall thickness was greater in the t rained than in the untrained arm of athletes, both values being greater tha n in sedentary subjects. Conclusions Asymmetrical training of the upper limbs is accompanied by a gr eater distensibility of the middle-sized arteries of the more trained side. This is not associated with asymmetrical changes in endothelial structure or function. It is associated with a greater wall thickness in the trained side, suggesting that, at least in part, a training-induced asymmetrical ch ange in wall structure (possibly with a predominance of more distensible ti ssues such as elastine and smooth muscle) is responsible, (C) 2001 Lippinco tt Williams & Wilkins.