This paper aims to present a study that would establish whether the sub-maximal effort produces modifications in the myocardial fiber morphology in rats with experimentally-induced heart failure.
The study was conducted on 40 rats, divided in four equal groups (Group I - normal rats who did not perform physical effort; Group II - normal rats who performed physical effort; Group III - rats on which heart failure was experimentally induced and who did not perform physical effort; Group IV - rats on which heart failure was experimentally induced and who performed physical effort).
The heart failure inducing protocol used doxorubicin. The physical effort was applied for 6 weeks, with a frequency of 3 sessions per week. At the end of the study, all animals were sacrificed, in order to perform histological examinations, taking samples from the heart for the photonic microscopy.
The recorded results highlight the fact that the modifications are important for the ultrastructure of the myocardial fibers, and performing a dosed physical effort plays a beneficial part for the myocardial ultramorphology.
The analysis of the results recorded for the lab rats groups allows one to say that the influence of sub-maximal physical effort on the positive progress of heart failure is determined, on one hand by the cardiac functional improvement, and on the other hand, by positive morphologic modifications, a proof of that being the photonic microscopy analysis results. | 
