Lifespan stops at death, but when does healthspan stop?

This editorial delineates the conceptual distinctions among lifespan, longevity, and healthspan in biogerontology. Lifespan is defined as the chronological duration from birth to biological death. Longevity refers to the capacity for survival beyond the species-typical average and is best understood probabilistically rather than as a predetermined limit. Healthspan, by contrast, lacks a uniform definition but is most commonly described as the period of life free from major chronic disease and significant functional decline. Healthspan is often considered to end with the onset of clinically significant impairment(s) that compromise physical or mental independence, irrespective of chronological age. Yet survival often persists beyond this point, highlighting the roles of medical, physiological, technological, and psychosocial compensations that enable continued existence despite markedly reduced health. Therefore, framing health through the lens of homeodynamic space positions it as the ability to sustain physical and mental independence adequately. Greater conceptual clarity is essential to enhance research alignment, improve cross-study comparability, and guide interventions that extend not merely chronological lifespan, but meaningful, context-sensitive healthy lifespan, even in the presence of disease(s). Biogerontology invites original research, review, and perspective articles addressing these issues.