This longitudinal study tested two different models of sympathetic nervous system influence on the early pathophysiology of essential hypertension. The first neurogenic model was evaluated by determining whether an excessively variable or reactive blood pressure in year 1 gave rise to excessive heart growth or left ventricular hypertrophy over a two year follow-up. The second neurogenic model was evaluated by determining if higher blood pressure exacerbated by personality, stress, and dietary sodium intake led to increased left ventricular hypertrophy at follow-up.