THE INFLUENCE OF ISOTONIC EXERCISE ON CARDIAC-HYPERTROPHY IN ARTERIAL-HYPERTENSION - IMPACT ON CARDIAC-FUNCTION AND ON THE CAPACITY FOR AEROBIC WORK

Intense physical training through isotonic exercises has controversial effects in individuals with moderate to severe hypertension, In this study, normotensive Wistar rats and rats with renovascular hypertensio n (Goldblatt II) were subjected to intense physical exercise involving two 50-min swimming sessions per day for a period of 12 weeks, At the end of the study, we evaluated the effect of training on arterial pre ssure, the capacity for aerobic work and cardiac function. Our results demonstrate that intense physical training has no effect on the arter ial blood pressure of normotensive rats or of animals with moderate re novascular hypertension, Hypertensive animals with cardiac hypertrophy require a greater period of training in order to attain the same capa city for aerobic work as normotensive rats. This difference may result from an inability of the former animals to increase cardiac complianc e, thereby impeding more extensive usage of the Frank-Starling mechani sm to subsequently increase the systolic cardiac performance, Cardiac hypertrophy induced by exercise did not summate with that induced by a rterial hypertension, Physical exercise normalized the end-diastolic l eft ventricular pressure in hypertensive animals without any correspon ding increase in the compliance of the chamber, The first derivative o f left ventricular pulse pressure (+/-dP/dt) was greater in the hypert ensive trained group than in the hypertensive sedentary rats, These ob servations suggest that a systolic dysfunction of the left ventricle i nvolving an elevated residual volume secondary to arterial hypertensio n may be corrected by physical exercise such as swimming.