How does the wear-and-tear theory explain aging?

The wear-and-tear theory of aging posits that biological organisms, much like machines, gradually deteriorate over time due to constant use and the accumulation of waste products that interfere with cellular function.12

While this theory suggests that cells simply "wear out," it is often criticized because it fails to fully account for the complex self-repair mechanisms inherent in biological systems, which distinguish living organisms from inanimate machines. A key corollary to this theory is the observation that insoluble particles, known as "age pigments," accumulate within cells over time. These deposits have been identified in nerve cells and the muscle cells of the heart, potentially contributing to age-related cellular dysfunction.12

It is important to note that the wear-and-tear theory is only one of several biological perspectives on aging; other models, such as those focusing on genetics or oxidative damage, provide additional insights into why humans age.2