The aging process is one that takes place at a cellular level. Each cell in your body has a telomere at each end of each chromosome. Every time the cell reproduces, a piece is clipped off. When the telomere is gone, it can no longer reproduce. Eventually, something happens and the cell dies.
Each daughter cell’s telomeres are also clipped. The process starts at conception. Initially, cells produce an enzyme called telomerase which adds new telomere bits onto a cell after it divides. Early in life, cells divide at a fantastic rate. As the cell reproduces, less telomerase is available to rebuild telomeres – plus the process is not 100% efficient. Over time some cells start hitting their limits. The process starts slowly and is unnoticeable at first but the count starts to build. Aging is a matter of reduced numbers of new cells and lower efficiency cells while the old ones start to die off.
Cell death is actually part of your body’s defenses. Cancer is nothing but uncontrolled cell division. A cell goes crazy and multiplies until the cells hit their telomere limit and that is the end of that. Your body has cancers all the time that die out this way, completely undetected. (Others get eaten by cells designed to attack anything out of place.) A dangerous cancer is one that has figured out a way to bypass these limits.
This isn’t the only reason we age. DNA becomes damaged over time for various reasons and repair is not 100%. This can be from radiation, oxidation, glycation, and other reasons. It stops producing needed proteins or produces deficient versions. Even with perfect telomeres, the cells begin to age. The two factors compound each other.
There is also cumulative damage to the body. A significant injury sustained during youth never heals completely. The same thing is true of the sun and your eyes and skin, too much loud noise and your ears, even radiation damage from natural sources to your body. This is why an older person will suddenly start feeling pain from an injury sustained 50 years earlier and then all but forgotten. It was mostly healed and the remaining scar was masked by natural vitality.
Your body accumulates many insults from minor cuts to major avulsions, strains, and sprains to broken bones, not to mention severe sunburns. Even long term exposure to UV that doesn’t burn slowly ages the skin and the eyes. (A good reason even us nudies should use sunscreen and UV blocking glasses during peak UV hours.) These old injuries return to make your old age feel even older.
If you kept your telomeres intact without allowing cancer to proliferate, you could live another 30 years. Scientists in Spain seem to have achieved this in mice. But these other factors I’ve mentioned would still eventually kill you.
The exercise we take to slow the aging process itself advances some age-related conditions. Exercise can lead to injuries in our joint and connective tissues that build up over time. Cartilage heals extremely slowly, more slowly than any other tissue. Tendons and ligaments are also slow. (The lesson here is moderation in everything, including exercise.) There are many people who were quite athletic in their youth and suddenly discover their joints fail them much earlier than expected.
OTOH, if you didn’t live a moderately vigorous youth, you haven’t built up the reserve strength to keep you active when your muscles start to atrophy. Your mind loses sharpness from inadequate exercise. You don’t have the cardiovascular fitness to slow the progress of heart & circulatory disease. Everyone has some degree of circulatory disease as they get older.
It is a tradeoff.
My current solution is moderation in all things – including moderation. I once read about this secret to happiness and longevity as a child in the book Lost Horizon. Of course I paid it no heed. I was young and healthy and immortal. Extremes in behavior, physical, sexual, pharmacological, appealed to a boy whose life was vapid and despairing. But as I age, my body doesn’t seem to allow me any other course.