Comparison of the Effects of Different Training Intensities on Resistance to Induced Cardiac Ischemia in Male Adult Rats

Document Type : Original Article

Abstract

Purpose: Myocardial infarction is one the main reasons of mortality in the world. One of the most important 
objectives of exercise training is to enhance stress tolerance and prevent heart attacks. Further studies are still 
needed on this type of prescribed exercise and heart condition improvement through exercise training (exercise 
preconditioning). The aim of this study was to compare the effects of two different exercise intensities (low 
and high) on the resistance rate in induced cardiac ischemia in male, adult rats based on performance (carotid 
±dp/dt as an indicator of ventricular contraction and relaxation rate) and chemical factors of heart.
Material and methods: Twenty four male, adult, Wistar rats were randomly divided into three groups 
(n=8): control (C), low intensity training (LIT) and high intensity training (HIT). At the end of week 14 of the 
training, all rats received isoproterenol (85mg/kg) through ip injection for 2 consecutive days, then 
performance factors (HR, DBP, SBP, MAP, RPP, carotid ±dp/dt) and Chemical indicator of tissue damage 
(tissue CTnI) were measured.
Results: Functional factors including SBP (Systolic Blood Pressure), DBP (Diastolic Blood Pressure), HR 
(Heart Rate), MAP (Mean Arterial Pressure), and RPP (Rate Presure Product) in the exercise groups were not 
statistically different from the control group, but carotid ±dp/dt levels in high and low-intensity exercise groups 
were significantly higher as compared to the control group (p<0.05).Tissue Cardiac troponin I levels in highintensity exercise group was significantly higher as compared to the control group (p<0.05).
Discussion and Conclusion: Our results showed that high-intensity exercise has protective effects against 
heart damage caused by injection of isoproterenol

Keywords

• Exercise intensity
• Isoproterenol
• Heart ischemia

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