How Life Span Differs from Life Expectancy?

Life span and life expectancy are related but distinct concepts. Life span refers to the maximum number of years an organism can live under ideal conditions. It represents biological limits determined by genetics. For humans, the maximum life span is around 120 years. Life expectancy, however, is the average number of years individuals in a population are expected to live, based on environmental, social, and health factors. It changes with access to healthcare, nutrition, lifestyle, and living conditions. For example, a human’s life span hasn’t changed much, but life expectancy has increased dramatically due to medical advancements and improved living standards. In short, life span sets the biological ceiling, while life expectancy reflects real-world outcomes. The difference highlights how genetics defines potential, while environment determines reality. Understanding both helps researchers identify ways to improve longevity and quality of life.