The employees of a vehicle factory (3351 persons) were examined for high blood pressure, over-weight and stress effects. Blood pressure increased with over-weight and age. However, over-weight increased with age up to 50 years. Furthermore, hypertension could generally be calculated from an increase in over-weight: this effect started already at a young age. The effect of age began at normal body-weight after 50 years and concerned systolic pressure (decreased elasticity of the windkessel arteries). The diastolic pressure increased, age-dependent, earlier, but at normal weight remained below 90 mm Hg. On single blood pressure measurement, 25% of subjects had a blood pressure above 160/95, 51% above 140/90 mm Hg. Among those under 20 years, 25% had a blood pressure above 140/90 mm Hg. The higher the initial level of pressure at a young age, the greater the later increase in blood pressure. Since the risk of cardiac and cerebrovascular complications steeply increases from 140/90 mm Hg and treatment of the milder (limit of normal) hypertension maintains patients well for longer, it is recommended that hypertension should be treated if on three measurements the pressure averages above 140/90 mm Hg. Pressure of 150/90 mm Hg is taken as a normal limit only in those above 60 years. Treatment of mild essential hypertension should at first be dietary: reduction of body weight, of salt intake and of alcohol consumption.