Early diagnosis of essential hypertension, preferably in the pre-hypertensive stage, is very important for the prognosis of affected subjects. Based on sporadic information in the literature it seems that people who are normotensive at rest but have an exaggerated hypertensive reaction to exercise have a greater risk of developing essential hypertension in future. The authors selected from protocols of ECG exercise tests a group of subjects with normal blood levels at rest but an exaggerated hypertensive reaction to a dynamic exercise. The control group was formed by people with a normal pressure reaction to a exercise the control group was matched as regards age, sex and basic anthropometric parameters. After a mean period of 7.8 years (range 5-10 years) it was revealed that while in the control group hypertension was manifested in 10%, in the group with an exaggerated hypertensive reaction to an exercise it was manifested in 33.3%. The mean original blood pressure readings at rest were significantly higher in people with a normal blood pressure reaction to an exercise and this difference persisted also at the end of the investigation. An exaggerated hypertensive reaction to a dynamic exercise is one of the prognostic factors for the development of essential hypertension and should be a reason for follow-up.