What is active lifespan?

Active lifespan refers to the period during which an individual is able to engage in daily activities, work, and enjoy life with a good quality of health and functional ability. It encompasses not only the years lived but also the duration of time spent in good physical and mental health, free from serious illness or disability. This concept emphasizes the importance of maintaining health and vitality as one ages, rather than merely focusing on the total number of years lived.