The 46 human chromosomes are shown in blue, with the telomeres appearing as white pinpoints
Image Credit: Hesed Padilla-Nash and Thomas Ried, the National Cancer Institute, a part of NIH
Mmm. You know how some highways have those grooves along the margins of the highway that will vibrate a drowsy driver awake? That is the design pattern of telomeres. They are at the end of a chromosome and indicate to the cell's replication machinery to stop copying the DNA at that point.
As you can imagine, it is slightly more complicated than that. The normal cell process is that the telomeres become naturally shorter every time the cell divides. Then when the telomeres are too short, the cell cannot divide or reproduce anymore.
Obviously that is a good thing if the cell happens to be cancerous, but we age at the cellular level when our cells can no longer replace themselves. Also when the telomeres becomes too short, the cell will often kill itself in a process called apoptosis.
Stressful jobs making us age prematurely explains that researchers have noted people with the most job stress have shorter telomeres. The 2,911 people sampled in the study were between the ages of 30 and 64. Shortened telomere length tied to dementia, mortality risk adds that the length of telomeres might be considered your biological age.