Editor-in-Chief Systems Physiology-Cardiopulmonary EFFECTS OF CHRONIC SWIMMING ON BLOOD PRESSURE AND SODIUM PUMP OF HYPERTENSIVE RATS

ABSTRACT Osiecki R, Malfatti CRM, Royes LFF, Sampedro RMF, Mello CF. Effects of chronic swimming on blood pressure and sodium pump of hypertensive rats. JEPonline 2008;11(5):35-41. In this study we investigated whether chronic exercise alters erythrocyte Na + ,K + -ATPase activity and hemodynamical parameters in adult male spontaneously hypertensive rats (SHR). Animals were randomly assigned to trained (n= 8) and untrained (n= 8) groups. Training was conducted 6 days/week for 12 weeks, alternating 60 and 90 min swimming sessions daily. At the end of the training program, animals underwent a 90 min swimming challenge and blood lactate was measured. Twenty hours after the challenge, a cannula was introduced into the right carotid artery for direct recording of the blood pressure and heart rate. After obtaining hemodynamical measures, blood was collected for erythrocyte Na + ,K + -ATPase activity. Training significantly reduced systolic (-9.2 %; p<0.01), diastolic (-13.3 %; p<0.01), mean blood pressure ( -11.3 %; p<0.001), resting heart rate (-14.5 %; p<0.001), plasma lactate levels (-44.8%; p<0.05) and a higher erythrocyte Na + ,K + -ATPase activity (41.5 % ; p<0.05). It is suggested that the exercise-induced increase of erythrocyte Na + ,K + -ATPase activity may contribute to decreased blood pressure