How does the wear-and-tear theory explain aging in cells and animals?

The wear-and-tear theory posits that cells and animals age because they simply wear out over time, much like mechanical systems. However, this analogy is limited because, unlike machines, biological organisms possess inherent mechanisms for self-repair.12

A central component of this theory is the accumulation of metabolic waste products within cells, which eventually interferes with normal cellular function. For instance, researchers have observed the buildup of insoluble particles known as "age pigments" in the heart muscle and nerve cells of humans and other animals.12

While this theory highlights the impact of accumulated cellular debris, it is considered an incomplete explanation for the complex process of aging. Modern biological research often looks toward more comprehensive models, such as genetic programming or oxidative damage theories, to better understand how environmental factors and internal cellular changes drive the aging process.2