Lifestyle-Associated Biomarkers of Cellular and Whole-Organism Aging: A Practical Roadmap for Human Geroscience Trials

Aging is a multidimensional biological process that is not adequately captured by chronological age alone. Geroscience—the study of biological mechanisms that drive age-related functional decline and disease susceptibility—therefore requires biomarker frameworks that can identify biological aging trajectories and assess whether lifestyle-associated interventions meaningfully influence aging-related pathways. In this review, we propose a practical, mechanism-based framework for studying lifestyle-associated effects on cellular and whole-organism aging in humans. We examine major biomarker domains, including DNA-methylation-based epigenetic aging clocks, cellular senescence-associated measures, senescence-associated secretory phenotype factors, inflammaging mediators, oxidative stress indicators, mitochondrial function, metabolic and nutrient-sensing pathways, proteomic and metabolomic signatures, microbiome-associated markers, and functional measures of frailty, mobility, cognition, and resilience. We also discuss criteria for biomarker selection in exploratory and multicenter trials, emphasizing biological relevance, analytical validity, responsiveness to intervention, feasibility, reproducibility, and clinical interpretability. Finally, we outline a practical study-design roadmap integrating biospecimen collection, repeated assessments, core and exploratory biomarker panels, and functional endpoints. A biomarker-guided geroscience strategy may provide a practical route for connecting mechanistic aging biology with clinically relevant human studies designed to preserve healthspan and functional independence.