A groundbreaking study out of UMichigan in 2019 that showed newly minted physicians who just started their specialty training (residency) will have their DNA age six times faster than the normal population

The telomeres at the end of DNA— which are sort of like aglets at the end of a shoelace—shrink 6 times faster when newly minted doctors are introduced to the new stress of training (long work hours 80-120hrs/week, little sleep, life and death situation etc).

Telomere shortening is a well-known hallmark of both cellular senescence and organismal aging. Telomere length is thus considered one of the most consequential biomarkers of chronological ageing, it’s maximum at birth and progressively decreases with age.

And it is irreversible.