When is health adequate for older adults? Optimal standards, patient-defined thresholds, and the weight of inequality.

This perspective distinguishes two standards that are often used as if they were interchangeable. Optimal health is a standard built by medicine and expressed through guideline targets and biomarkers. Adequate health is the threshold of functioning that allows a person to live in a way they themselves experience as sufficient and dignified. Building on the concept of homeodynamic space as the biological substrate of adequate independence, on the older salutogenic tradition that asked what sustains health rather than only what causes disease, and on clinical evidence that aligning care with patients' own priorities can reduce treatment burden without worsening the outcomes patients themselves value, this article argues that optimal health is doctor based while adequate health is patient based. In any population ageing under conditions of socioeconomic inequality and health system fragmentation, the distance between the two standards is wide and unevenly distributed within the same country. Adequate health for an older adult must therefore be defined relative to the resources, culture, attitude, and priorities actually available to that person, not only against a uniform biomedical ideal that a large share of any population has no realistic path to reach. The argument is developed using data and policy from Mexico, chosen for the scale of its ageing population and the sharpness of its socioeconomic gradient, but the distinction it defends applies wherever health systems and biomarkers are used to judge the value of an older life.