The impact of high intensity interval training and moderate intensity continious training regimes on cardiodynamic parameters in isolated heart of normotensive and hypertensive rats.

This study was aimed to assess the impact of high intensity interval training (HIIT) vs. moderate intensity continious training (MIT) on cardiodynamic parameters in isolated rat heart. Wistar albino rats were randomly assigned to groups according to running protocol: sedentary control (CTRL), MIT, HIIT; spontaneous hypertensive sedentary control (SHR), spontaneous hypertensive rats (SHR) + MIT and SHR + HIIT. HIIT groups performed the running in 5 sprints x 45-55m/min for 30-90sec, with 2 mins rest after each sprint, while MIT groups performed the running of 10-15m/min for 1h with 3 mins rest/100m, both protocols were implemented 5 days/week over 4 weeks with one week of adaptation before protocols started. Isolated rat`s hearts were perfused according to Langendorff technique at gradually increased coronary perfusion pressures (40-120 cmH2O). Using sensor placed in the left ventricle, we registered: maximum and minimum rate of pressure development in the left ventricle, systolic and diastolic left ventricular pressure and heart rate. Coronary flow was measured flowmetrically. MIT was connected with cardiac depression in normotensive conditions, while HIIT leads to cardiac depression in hypretensive rats. HIIT induced more significant increase of contractile and relaxation parameteres of the isolated rat heart, especially in hypertensive animals.