We age because of a combination of intrinsic biological processes and external environmental factors that cause damage to our cells and tissues over time. Cellular aging involves cells losing their ability to function properly as they divide and accumulate damage, especially to DNA and telomeres, which are protective caps on chromosomes that shorten with each cell division. Environmental factors like UV radiation, pollution, and lifestyle also contribute to cell damage and aging. This damage accumulates and impairs tissue and organ function, leading to the physiological changes known as aging. Additionally, processes like decreased cellular repair, chronic inflammation, and reduced autophagy (cellular recycling) play key roles in accelerating aging.
Key Reasons for Aging
- Cellular Damage: DNA undergoes damage from both internal metabolic processes and external sources like UV light and toxins. Repair mechanisms become less effective with age, leading to accumulation of mutations and cellular dysfunction.
- Telomere Shortening: Telomeres protect chromosome ends but shorten with each cell division. When too short, cells stop dividing or die, contributing to tissue aging and loss of regenerative capacity.
- Environmental and Lifestyle Factors: Exposure to pollutants, smoking, poor nutrition, and sunlight cause additional damage to cells and accelerate aging processes.
- Inflammation and Autophagy Decline: Chronic low-level inflammation ("inflammaging") damages tissues, and reduced autophagy means less cellular clean-up, further accelerating aging.
Theories on Aging
Scientists do not agree on a single cause but have over 300 theories. Broadly, aging results from a mix of genetic programming and accumulated damage. Some evolutionary theories suggest aging evolved as a way to make room for younger generations. Aging affects each person differently depending on genetics and environment.
In summary, aging is a complex process driven by accumulated cellular damage, genetic factors like telomere shortening, reduced cellular repair and recycling, and environmental exposures that gradually impair the body's functionality.
