Senescent "Zombie" Cells
They quit dividing, refuse to die, and poison the cells around them. You're collecting more every year.
Grounded in the research on cellular senescence
1. Hit the wall
In 1961 Leonard Hayflick and Paul Moorhead noticed human cells in a dish stop dividing after roughly 50 splits. That ceiling is the Hayflick limit. Every replication shaves the telomere caps off your chromosomes; once they get critically short, the cell can't safely copy its DNA again. So it slams the brakes on division. Permanently. That's the first way a cell goes senescent.
2. Arrest, don't die
Normally a damaged cell would self-destruct (apoptosis) and get cleared. The senescent one doesn't. Damage trips the p53/p21 and p16 alarm systems, which lock the cell cycle shut, but the same signals also block the death program. So the cell sits there. Alive, metabolically active, never dividing, never leaving. That's the "zombie" part: undead by design, not laziness.