IJCS | Volume 31, Nº5, September / October 2018

DOI: 10.5935/2359-4802.20180046 505 ORIGINAL ARTICLE International Journal of Cardiovascular Sciences. 2018;31(5)505-512 Mailing Address: Daniele Jardim Feriani Avenida Érico Veríssimo, 701. Postal Code: 13083-851, Barão Geraldo, Campinas, SP - Brazil. E-mail: dani_feriani@hotmail.com Protective Effects of Accumulated Aerobic Exercise in Infarcted Old Rats Daniele Jardim Feriani, 1,2 Hélio José Coelho-Júnior, 2 Maria Cláudia Irigoyen, 3 Bruno Rodrigues 2 Universidade São Judas Tadeu; 1 Mooca, SP - Brazil Universidade Estadual de Campinas (UNICAMP), 2 Campinas, SP - Brazil Instituto do Coração (InCor) - Faculdade de Medicina da Universidade de São Paulo, 3 São Paulo, SP - Brazil Manuscript received September 19, 2017, revised manuscript December 19, 2017, accepted January 16, 2018. Abstract Background: Aerobic exercise exerts cardioprotective effects on myocardial infarction. However, there is lack of information about the possible protective effects of continuous or accumulated aerobic exercise performed prior to myocardial infarction in aging. Objective: To evaluate the preventive effects of continuous or accumulated aerobic exercise on physical capacity, pulmonary congestion and ventricular weight in rats submitted to myocardial infarction. Methods: Old male Wistar rats were divided into four groups: sham control, sedentary infarcted, continuous aerobic exercise submitted to myocardial infarction, and accumulated aerobic exercise submitted to myocardial infarction. Body weight and maximum speed were evaluated at the beginning and at the end of the protocol. Trained groups performed continuous (1 h a day) or accumulated (30 minutes in the morning and 30 minutes in the afternoon) exercise. All groups, except the sham control, were submitted to myocardial infarction surgery at the end of the protocol. Heart, skeletal muscles, as well as wet and dry lung were weighed. The significance level in statistical analysis was established at p < 0.05. Results: Both continuous and accumulated exercise caused an increase in physical capacity in rats, as well as prevented its further impairment after myocardial infarction, and in the accumulated exercise group this prevention was greater. The continuous exercise group demonstrated an increase in lung water content, while the accumulated exercise group presented a reduction in body weight and an increase in left ventricle relative weight. Conclusion: In conclusion, the data of the present study indicate that accumulated aerobic exercise present a better protective effect than continuous aerobic training in the context of myocardial infarction and aging. (Int J Cardiovasc Sci. 2018;31(5)505-512) Keywords: Myocardial Infarction/prevention & control; Exercise; Physical Endurance; Aging; Rats. Introduction Myocardial infarction (MI) is one of the leading causes of death worldwide. Its pathophysiology consists of myocardial cell deathdue to prolonged ischemia resulting from the occlusion of coronary artery ramification. After MI, a process of ventricular remodeling is initiated, in which cardiac changes - such as ventricular dilatation - accompanied by increased sympathetic activity occur as compensatory mechanisms that, at the beginning, regulate survival but, over time, worsen the prognosis of the infarcted patient.¹ , ² In aging, due to changes such as stiffening of the arteries, which in turn results in increased afterload on the left ventricle, systolic blood pressure and changes in the left ventricular wall, the elderly are more susceptible to develop cardiovascular diseases, such as MI. 3,4 In this sense, physical training has been used as an important strategy in the management of cardiovascular diseases, due to its several benefits, such as reduction of adiposity and increased heart rate variability, thus contributing to prevent cardiac events. 5 However, if a