The problem of cardiovascular regulation during aging has received insufficient attention, despite its high social significance. The common pathogenesis of cardiovascular regulation disorders in experimental animals and in elderly people makes it relevant to study the mechanisms of myocardial contractility regulation in a comparative experiment on laboratory animals of different ages. In order to establish the features of length-dependent mechanisms of healthy myocardial contractility regulation during aging, length-dependent changes in the characteristics of force, electrical activity and changes in the intracellular concentration of calcium ions (calcium transient or CaT) in the myocardium of the right ventricle of groups of young (1 month) and old (2.5 years) rats were assessed. The experiments were carried out on the trabeculae of the right ventricle of the hearts of male Wistar rats. In the isometric contraction mode, with varying degrees of stretching, the indices of mechanical tension, CaT and transmembrane action potentials (AP) were recorded. It has been experimentally established that old animal has a smaller amplitude of isometric tension, a lower rate of development of isometric tension, and a longer AP in comparison with young animals. For the first time, age-related features of length-dependent changes in the CaT curves obtained at different preloads of the ventricular myocardium, with their superposition, have been established. In old animals, the duration of the CaT decline by 30% of its amplitude is significantly greater than in young animals. The effect of the degree of acto-myosin overlap on the intracellular kinetics of calcium ions in the ventricular myocardium strips of rats of different ages has been shown, using the developed method of the difference of the curves of calcium transients. The relative amplitude and area of segment III of the CaT difference curves are significantly greater in young animals, in comparison with old ones.