Patients with slight increase in blood pressure levels have an increased cardiovascular risk. In particular this has been demonstrated also in subjects with high-normal blood pressure in whom an exaggerated blood pressure increase, during exercise, and structural left ventricular abnormalities have been shown. On the other hand, the last American and European guidelines for management of hypertension recommend more aggressive treatment in young-middle aged subjects to achieve a better control of cardiovascular risk due to blood pressure increase. In agreement with these recommendations the investigators share the idea that a good blood pressure control should be achieved not only at rest, but also during psycho-physical stress conditions that frequently occur during daily life. On this basis, the investigators decided to evaluate the efficacy and tolerability of the association of valsartan and hydrochlorothiazide (160 an 25 mg daily, respectively) in patients with high-normal blood pressure and first degree arterial hypertension with evidence of organ damage.