What Happens to Telomeres as We Age?

When we are born, generally our telomeres are at their longest. With every cell division throughout the course of our life, our telomeres lose a bit of their DNA. In addition to the normal replicative processes of the cell, telomeres are also negatively impacted by oxidative stress. Oxidative stress is a cellular condition that describes the cumulative damage done by an imbalance between the body’s production of free radicals and its’ ability to detoxify their harmful effects through antioxidants. Oxidation stress occurs in the normal course of our body’s metabolism, in addition to other external stressors, including but not limited to:
• Poor diet
• Excessive alcohol consumption
• Sedentary lifestyle
• Other sources of oxidizing activity, such as traffic fumes or cigarette smoke
With age and accumulated exposures to various sources of oxidative stress throughout our lifetimes, telomeres gradually shorten, until cells can no longer replicate. This shortening process acts as an aging clock counting down the remaining life of the cell. At a certain point, chromosomes in the cell reach a critical length and can no longer be replicated. When this occurs, the cell enters into a state of growth arrest, known as “cellular senescence,” which is the cellular equivalent of aging.