Scientist Aubrey de Grey, a controversial academic, thinks it’s possible to end ageing and extend the human lifespan for as long as 1000 years. Aubrey has spent millions of his own and billionaire PayPal co-founder Peter Thiel’s money, pursuing the quest for near-eternal life in the hope that they’ll find out a way to live forever.
But, why do we age? The answer is more complex than merely the passage of time, and there are many competing hypotheses.
Here are some science-based ideas as to what’s happening inside the cells in your body as you age.
1. Oxidative Damage: We need oxygen to live, but, paradoxically, the byproducts of oxygen reactions in the body are what age us. These byproducts, called free radicals, are highly unstable due to an odd number of electrons. In their quest for an even number of electrons, they manage to damage our cells. Antioxidants are molecules that work to neutralize free radicals before they can cause injury, but our levels of antioxidants fall as we age– and so the damage piles up.
2. Cellular Debris: The cells in our body have quite a few jobs to do to keep us alive on a daily basis. One of the tasks on the body’s to-do list is waste removal — getting rid of the byproducts of cells’ functions and clearing out the dead cells. But other priorities, such as fending off free radicals, trump taking out the trash. As we age, the trash builds up, taking up space and hindering regular cell function. It also sometimes draws the fire of the immune system — meaning it’s associated with autoimmune diseases.
3. Glycation Sugars in the body like to bind with proteins and lipids. Collagen and elastin just so happen to be the type of protein that sugars like. They’re also the materials that give your skin its firmness and shape. Once sugars bond with the collagen and elastin, the advanced glycation end products (AGEs) that result destroy the structure of the skin, causing sagging, wrinkles and crepiness.
4. Telomere Shortening: Telomeres bookend our chromosomes and are meant to keep them from getting stuck to other chromosomes or deteriorating. But every time a cell divides, these protective caps get shorter. Cell death occurs when there isn’t enough telomere left to repeat the cell cycle. This shortening is associated with cellular senescence, or the limit to how many times a cell can divide. Over time, cells are less able to repair themselves and more likely to develop mutations or succumb to disease in response to stress. They stop growing. This can be a good response — if we could figure out how to make cancer cells stopproliferating, that would be a huge breakthrough. But with regular cells in the body, it simply leads to degeneration.
5. DNA Damage: A number of factors cause DNA damage, including oxidative stress (see #1 on this list), UV light and cigarette smoke. DNA damage can be repaired by enzymes, but only at a certain point. Once a mutation is in both strands of DNA, it can’t be fixed — and it will replicate every time the cell does. Some mutations affect a cell’s ability to reproduce, so when a cell’s DNA is damaged and it can’t complete cell division often, we have a lemon.
6. Inflammation: Acute inflammation is a good thing — a response to injury or infection that protects the body. You burn your skin, and your body immediately swoops in to begin fixing it, resulting in redness, swelling and pain. But chronic inflammation is a misuse of the function. The inflammatory response kicks in and never stops, interfering with cell functioning and repair. Autoimmune diseases, like rheumatoid arthritis and multiple sclerosis, are associated with chronic inflammation. Persistent infections and allergies, too. Some cells, like skin cells, have high regenerative capacity and are easily repaired. But brain cells, cardiac cells and some muscle cells are more vulnerable to damage.
7. Cellular Energy Decline Mitochondria: These little organelles in your cells, produce the body’s energy source, adenosine triphosphate (ATP). But because the mitochondria do this in the presence of oxygen, they become exposed to the free radicals described in #1 on this list. Free radicals cut into the mitochondria population and impair their functioning, leaving the body with less fuel. With a smaller ration of energy, the body diverts it to only what’s necessary to survive. In other words, you’re getting by with the little energy that’s left, but you don’t have enough to fight off disease and degeneration.
8. Insulin Resistance: The hormone insulin is supposed to lower blood sugar by getting the sugar from your blood into your cells for energy. But the modern diet tends to throw insulin into overdrive — and eventually the cells simply stop responding to it. When they stop responding, the pancreas pumps out even more insulin so they will respond (but they don’t). When sugar stays in the blood, the cells are missing their energy supply. But fat cells are the last type of the cell that becomes resistant to insulin, so guess where all the fuel is going? The insulin resistance cycle leads to obesity and degenerative disease.
9. Hormonal Decline: Human growth hormone (HGH) levels fall beginning in middle age. The pituitary gland in your brain just stops making it. The result is more body fat and less muscle, less bone density, sagging skin, low energy — in short, all the symptoms of ageing.
Until science finds a way to counteract realities such as DNA damage, ageing is still a fact of life – although some of the symptoms associated with it, like loss of vitality, don’t have to be.
Tell us in the comments – would YOU want to live forever?