Biomarkers used to track benefits of anti-aging therapies can be misleading, suggests the 'Lifespan Machine'

We all grow old and die, but we still don't know why. Diet, exercise and stress all affect our lifespan, but the underlying processes that drive aging remain a mystery. Often, we measure age by counting our years since birth and yet our cells know nothing of chronological time—our organs and tissues may age more rapidly or slowly regardless of what we'd expect from counting the number of orbits we take around the sun.