Abstract des Autors

Doppler sonography (TCD) provides the possibility to continuously record the middle cerebral artery (MCA) flow velocity during exercise on the bicycle ergometer. 15 cyclists, 10 young junior high school students, 15 healthy volunteers, and 27 cardiology patients were examined until exhaustion (max. 400 W) and during 7 min of recovery. Besides TCD, ECG, heart frequency, and blood pressure were measured. Comparing groups of persons of different age and limits of performance, the cerebrovascular effects of exercise are similar at equal relative work loads. The mean MCA flow velocity increases during aerobic exercise by 15-30%. When increasing the load in steps of 50 W, a marked initial decrease of mean and diastolic flow velocity is observed until heart rate and blood pressure reach the steady state level. At maximum load, the MCA flow velocity is about 10-20% below the control value in trained as well as in untrained persons. When maximum performance is stopped abruptly, the mean flow may drop critically with a diastolic flow near zero. The control value is regained after 5-7 min of recovery. In conclusion, TCD may provide important data during ergometric examinations. Verf.-Referat