Alzheimer's disease (AD) is a progressive neurodegenerative disease that impairs memory and cognitive judgment. It is the leading cause of dementia in late adult life and is associated with a significant social burden and increased morbidity and mortality in the elderly. Because of mixed effectiveness of medications, exercise has been considered as a treatment for pre-clinical AD, late stage AD, and as a prevention strategy. Exercise appears to improve brain blood flow, increase hippocampal volume, and improve neurogenesis. Prospective studies indicate that physical inactivity is one of the most common preventable risk factors for developing AD and that higher physical activity levels are associated with a reduced risk of development of disease. Exercise as a treatment for AD shows improvement in cognitive function, decreased neuropsychiatric symptoms, and a slower decline in activities of daily living (ADL). Exercise has been shown to have fewer side effects and better adherence compared to medications.