Aging is a complex biological phenomenon. Because health can vary greatly even among persons of the same chronological age, biological age, an integrative measure of physiological and molecular deterioration, may be a more useful construct for promoting longevity. Biological aging does not represent a "fixed" process; rather, it can be reversible. Many markers of biological aging exist. Epigenetic clocks use patterns of aging-related DNA methylation to predict morbidity and mortality, but other omics methods, as well as clinical biomarker-derived phenotypic aging, can be used to assess aging in real-time. However, implementing these into clinical practice has been challenging. Race, sex, and chronological age are all modulators of the predictive performance of current biological aging measures. Also, while there are numerous ways to intervene on unhealthy aging trajectories, such as precision nutrition strategies, tailored physical activity regimes, and pharmaceutics, integration of these strategies into standard clinical care has been limited. Here, we propose an exploratory framework that leverages longitudinal assessment of biological aging to evaluate success of personalized longevity strategies. Collectively, advances over the past decade, including validation of complementary aging measures, increasing digitalization of healthcare data, and rapid growth of aging-focused research have brought the field closer to this goal. While important barriers persist, these developments suggest a future in which precision longevity medicine meaningfully advances healthspan and lifespan.
