Τhe rate of patients suffering from mild cognitive impairment or any type of dementia has been constantly on the rise. Considering that no effective treatment of dementia has been discovered to date and that drug use can have numerous side effects, there is an urgent need for the application of alternative, non-pharmacological interventions. To this end, the aim of this study was to investigate the effects of physical activity on the cognitive impairment of the elderly, and its use as a form of non-pharmacological intervention for the treatment of dementia. Taking a review of the relevant literature, as its data collection method, this study examined peer-reviewed papers published between 2010 and 2018 that met the criteria for their inclusion. The articles were drawn from three electronic databases (PubMed, ScienceDirect and Web of Science), and were examined with regard to the populations under consideration, research design, type of intervention programs and assessment tools applied. The vast majority of these research papers tend to support that physical activity offers significant benefits to people suffering from Alzheimer's disease or other dementias. Specifically, it helps stabilize and improve cognitive function as well as reduce and delay the onset of severe neuropsychiatric symptoms such as depression, confusion, apathy, etc. In addition, physical exercise plays an important role in improving the executive functioning of patients with dementia, increasing autonomy in their everyday activities and reducing the risk of falls. In conclusion, recent research shows physical activity to be a promising intervention for the prevention and non-pharmacological treatment of dementia in that it contributes to the improvement of patients' quality of life. However, results vary according to the particularly characteristics of the exercise under review, such as type, intensity, frequency, and duration. It is therefore important to gain both awareness and understanding of the specific factors that give physical activity its therapeutic potential leading to the development of exercise programs designed specially to treat dementia.