“ According to research into the molecular changes associated with aging, humans experience two drastic lurches forward, one at the average age of 44 and the other at the average age of 60.
"We're not just changing gradually over time; there are some really dramatic changes," geneticist Michael Snyder of Stanford University said in August when the study was published.
"It turns out the mid-40s is a time of dramatic change, as is the early 60s.”
https://www.sciencealert.com/study-finds-humans-age-faster-at-2-sharp-peaks-heres-when-they-hit