Chronological vs. Biological Age Chronological age is simply the amount of time that has passed since birth. In contrast, biological age quantifies the accumulation of molecular and cellular damage, reflecting an individual's functional state and susceptibility to disease and death. Because individuals age at different rates due to genetics, lifestyle, and environment, biological age is often a more accurate predictor of healthspan (years spent in good health) and lifespan than calendar years.

Measuring Biological Age Scientists have developed various "clocks" and biomarkers to estimate biological age:

• Epigenetic Clocks: These measure DNA methylation (chemical tags on DNA that regulate gene expression).

◦ First-Generation (e.g., Horvath, Hannum): Trained to predict chronological age.

◦ Second-Generat ...