Biology of Aging

Aging is the gradual decline in a cell's and organism's ability to maintain itself, and biogerontology is the field that studies why and how that happens. Researchers describe it through a handful of interacting mechanisms — often grouped as the "hallmarks of aging" — including genomic instability, telomere shortening, epigenetic drift, loss of protein quality control, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered cell communication. No single theory explains aging on its own; most current models treat it as several of these processes accumulating together over time.

A growing toolkit of aging biomarkers — molecular and physiological measurements like epigenetic clocks, inflammation markers, and physical performance tests — lets scientists estimate biological age separately from calendar age. That distinction matters because it gives researchers a way to test whether an intervention is actually slowing the underlying process, not just masking symptoms.