Inclusion Criteria:  Men and women 65 - 80 years. Able to speak and read fluent Spanish. Living in community during the study. Reliable means of transportation. Being physical inactive (i.e., not to be participating in the last 6 months in any resistance exercise program, or accumulating less than 600 METS/Week of moderate-vigorous physical activity). Classified as cognitively normal according to Stics-m MMSE and MOCA tests.  Exclusion Criteria:  Ambulatory with pain or regular use of an assisted walking device. Medical contraindication for inclusion in an exercise program. Neurological condition (Multiple Sclerosis, Parkinson Disease, Dementia) or brain injury (traumatic or stroke). Current diagnosis and treatment of a DSM-V Axis I or II disorder including major depression and seeing a psychologist, therapist, or psychiatrist. History of major psychiatric illness including schizophrenia, general anxiety disorder or depression (GDS-30>=15). Current treatment for congestive heart failure, angina, uncontrolled arrhythmia, deep venous thrombosis or other cardiovascular event. Myocardial infarction, coronary artery bypass grafting, angioplasty or other cardiac condition in the past year. Current or previous treatment for any type of cancer. Type I Diabetes or uncontrolled Type II Diabetes defined as Insulin dependent or Hba1C greater than 10. Recent treatment for alcohol or substance abuse. Presence of metal implants (e.g., pacemaker, stents, joint replacement) that would be MRI ineligible. Claustrophobia. Color blindness. Diagnosis of COVID-19 with hospitalization in intensive care unit. Any other consideration that interferes with the study aims and could be a risk to the participant, at the discretion of the researcher.