Epidemiological studies have found a link between aircraft noise exposure and increased incidence of arterial hypertension and thus cardiovascular disease. The underlying pathophysiological mechanisms are not yet fully understood. The kidney acts as a long-term regulator of blood pressure and controls the extracellular sodium and water balance. Significant renal mechanisms of blood pressure regulation are the renin angiotensin system, renal sympathetic activity and sodium excretion. Animal work and clinical studies show that mental stress affects the renal plasma flow and urinary sodium excretion. The investigators observed a lower sodium excretion in situations of mental stress in subjects at risk for developing arterial hypertension. In healthy volunteers, a 30-minute mental stress test resulted in increased glomerular filtration rate, filtration fraction and an increase in urinary sodium excretion. In this pilot study the investigators analyzed the influence of 30 minutes standardized aircraft noise on renal and central hemodynamics.