en Gross Anatomy Gross Anatomy Original Original <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Tahoma;"><span style="line-height:2;"><strong>Introduction</strong>: Aging is a physiological process that affects heart function. Training is known as a factor accelerating heart output, especially in aged individuals. In the present experimental study, the authors aimed to evaluate how high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) affect autophagy, cardiac remodeling, and cardiac function.&nbsp;<br> <strong>Methods</strong>: Twenty-four male Wistar rats, approximately 20 months old, were divided into three groups of control, HIIT, and MICT. The training programs lasted for eight weeks. Aerobic power and training capacity were also assessed. Two-dimensional echocardiography was also applied to assess cardiac indices. At the end of the experiment, tissue sampling of cardiac tissue was applied, and gene expression was assessed using the qRT-PCR technique. Data were analyzed using SPSS software, version 19.<br> <strong>Results</strong>: After HIIT and MICT, no significant changes were detected regarding the animal weight. Also, mTORC1, Atg16, and Atg7 gene expression and ejection fraction (EF) and fractional shortening (FS) were accelerated in HIIT and MICT groups compared to control animals. Besides, the collagen type 3 (COLIII) gene expression, left ventricular end-diastolic diameter (LVEDD), and left ventricular end-systolic diameter (LVESD) showed a significant increase (p<0.05) in HIIT and MICT animals than control.<br> <strong>Conclusion</strong>: Training can potentially improve cardiac output in older adults. Besides, HIIT seems more effective than MICT.</span></span></span></div> Aging, Cardiac output, Echocardiography, High-intensity interval training (HIIT), Moderate-intensity continuous training (MICT), mTORC1, Atg16, Atg7, COLIII, Left ventricular end-diastolic diameter (LVEDD), Left ventricular end-systolic diameter (LVESD), 7 14 http://anatomyjournal.ir/browse.php?a_code=A-10-415-1&slc_lang=en&sid=1 Azadeh Taheri azadetaheri1992@gmail.com 10031947532846007516 10031947532846007516 No Department of Exercise Physiology, Faculty of Literature, Science and Research Branch, Islamic Azad University, Tehran, Iran. Mandana Gholami Gholami_man@yahoo.com 10031947532846007517 10031947532846007517 Yes Department of Physical Education and Sport Sciences, Faculty of Literature, Humanities and Social Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran. Behzad Bazgir Bazgirbehzad@yahoo.com 10031947532846007518 10031947532846007518 No Exercise Physiology Research Center, Life Style Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran. Hossein Abednatanzi abednazari@gmail.com 10031947532846007519 10031947532846007519 No Department of Professional Physical Education and Sport Science, Faculty of Literature, Science and Research Branch, Islamic Azad University, Tehran, Iran.