In this study, we investigate whether the levels of oxidized LDL and arterial elasticity differ between patients with metabolic syndrome and their physically active controls. Oxidized LDL is assessed by a two-site ELISA immunoassay (Mercodia, Uppsala, Sweden). The capacitive elasticity of large arteries (C1) and the reflective elasticity of small arteries (C2) are automatically assessed by the CR-2000 as a mean of five most similar pulse waves appearing during the measurement. C1 identifies the elastic properties of aorta and other large arteries, C2 the endothelial function of the microvascular circulation. Proper statistical methods are used to reveal possible differences and their significance between the patients and controls.