[Hypotension following maximum physical exercise. Evaluation of hemodynamic and humoral mechanisms]

The period after exercise has received little attention although there are rapid and arge changes in the loading conditions of the heart and circulation which may precipitate hypotension or arrhythmias. Little is known of the time course of the recovery of cardiac output and humoral changes occurring during this periods. After a single bout of prolonged muscular exercise, systolic and diastolic blood pressure decrease, sometimes for several hours. In a recent controlled study for the possible effects of the expecting of the exercise, a reduction in diastolic blood pressure was observed particularly in the first 10 min and lasting to 60 min. The mechanisms of the acute hypotensive effect of upright dynamic exercise have not yet been clarified. Little is known of the time course of the recovery of cardiac output, humoral and autonomic changes occurring during this period. Conflicting data are presented by different authors. The aim of the present study was to study the role of the haemodynamic and humoral changes in the modifications in blood pressure occurring in the hour of recovery after maximal exercise in normal subjects. Nine normal male volunteers (age: 28:34 years) have been studied on 2 separate days. Subjects were studied on a non-exercise (control) day (the subjects maintained the upright position for 30 min, followed by 60 min supine) and an exercise day (maximal upright bicycle exercise followed by supine rest for 60 min), in a random order. The following data have been recorded before the test and serially during 60 minute supine: systolic and diastolic blood pressure, heart rate, haemodynamic changes (by suprasternal aortic Doppler), and humoral changes (renin).(ABSTRACT TRUNCATED AT 250 WORDS)