This study material deals with the topic of wellness, aging, and the quality of life of the senior population from a holistic perspective. The theoretical part characterizes the process of aging and old age from biological, psychological, and social points of view, describes demographic developments, and focuses on the determinants of seniors‘ quality of life, including nutrition and measurement methodologies. A significant portion of the work is dedicated to the specifics of physical activities and the design of reconditioning and wellness programs tailored to the fitness levels and health conditions of older adults. The practical and research section analyzes the physical and wellness activities of seniors aged 65+ and presents results from selected comparative studies focusing on physical fitness, leisure time activities, and quality of life among seniors living under various conditions and settings.