Pronouncing on the fitness of children operated upon for coarctation of the aorta to practise sports, as well as on the nature and level of this activity, depends, to a great extent, upon their blood pressure profile at exercise (BPE) as measured by an exercise test on an ergometric bicycle. We studied thi profile in 43 children aged 11.7 +/- 2.5 years who had undergone surgery for coarctation of the aorta (isolated in 93 p. 100 of the cases) at the age of 3.8 +/- 3.2 years Systolic arterial pressure (SAP) in the upper limbs was normal at rest in 80p. 100 of the children but reached abnormal values at exercise in 81 p. 100 and even exceeded 200 mmHg in 16 p. 100. Diastolic arterial pressure (DAP) in the upper limbs was sometimes slightly elevated at rest, but it clearly decreased at exercise and became normal in all cases. This suggested that systolic hypertension at exercise was due to low peripheral resistance and either to an exercise-induced isthmic gradient or to a poor vascular impedance. As a result of this study, we warn such children against playing sports with a strong static stress (e.g. martial sports) or with a risk of thoracic trauma (e.g. rugby). For the other sports, we make no reservation when the BPE is normal, and we forbid competitions when the BPE is abnormal but the SAP at exercise remains below 200 mmHg. Beyond this value, children must be investigated for residual coarctation of the aorta which may be amenable to a specific treatment.