The chapter discusses the limitations of the World Health Organization's (WHO) definition of health, which has been criticized for being too absolute and failing to account for the rise of chronic diseases. The current definition, formulated in 1948, emphasizes complete physical, mental, and social well-being, but it is seen as counterproductive in the context of aging populations and changing disease patterns. The authors propose a reformulation of health based on the ability to adapt and self-manage in the face of social, physical, and emotional challenges. This new concept is more dynamic and practical, focusing on resilience and coping mechanisms. The chapter also explores the operationalization of this concept in physical, mental, and social health domains, and suggests that measurement tools should reflect these dynamic features. The authors conclude by advocating for a fresh, 21st-century approach to conceptualizing human health that involves ongoing discussions with various stakeholders.The chapter discusses the limitations of the World Health Organization's (WHO) definition of health, which has been criticized for being too absolute and failing to account for the rise of chronic diseases. The current definition, formulated in 1948, emphasizes complete physical, mental, and social well-being, but it is seen as counterproductive in the context of aging populations and changing disease patterns. The authors propose a reformulation of health based on the ability to adapt and self-manage in the face of social, physical, and emotional challenges. This new concept is more dynamic and practical, focusing on resilience and coping mechanisms. The chapter also explores the operationalization of this concept in physical, mental, and social health domains, and suggests that measurement tools should reflect these dynamic features. The authors conclude by advocating for a fresh, 21st-century approach to conceptualizing human health that involves ongoing discussions with various stakeholders.