In 10 male juvenile hypertensives WHO stage I who are active in sports echocardiographic investigations were performed at rest and on exertion (up to 2 Watt/kg body-weight) without therapy as well as 1 hour after sublingual administration of 20 mg nifedipine and after a six-week treatment with 3 times 20 mg nifedipine a day. 51 normotensives of the same age served as reference test persons. The antihypertensive effect was distinct, but not so expressive as under the beta-blockade. From the behaviour of the heart rate (reduction under permanent therapy) of the stroke volume (increase to the highest step of exertion) and of the reduction of blood-pressure can be concluded to an economizing effect of the central haemodynamics by nifedipine on exertion. Negative inotropic effects could be excluded particularly from the behaviour of the medium circumferential speed of the velocity of the shortening of fibres on exertion. Nifedipine can be recommended for the treatment of bodily active hypertensives, when the administration of beta-blockers is not to be represented.