What Really Causes Ageing?
Share
Ageing is something we all experience, but understanding why we age is still one of science’s biggest puzzles. Some people live longer and healthier lives than others, and scientists are trying to find out why. Theories about ageing have changed over time, and today, researchers mainly focus on two big ideas: ageing happens because of damage that builds up over time, or it is part of a built-in biological program. Let’s explore these ideas in simple terms.
Ageing: More Than Just Getting Old
Most people think of ageing as just getting older, but it’s actually a gradual loss of body function that affects nearly every part of our bodies. As we age, we become more likely to get diseases and injuries, and it becomes harder to recover. This process doesn’t start suddenly in old age—it begins much earlier in life, sometimes even before we’re fully grown.
Scientists have found that different parts of the body age at different speeds. For example, the brain, liver, and skin may not all show signs of ageing at the same time. This makes it harder to study and understand the ageing process.
The Wear and Tear Theory: Errors and Damage Over Time
One major theory says we age because of tiny mistakes that add up in our cells over time. These mistakes can happen because of things inside our bodies, like metabolism, or outside, like pollution or radiation. This is known as the “error-based” theory of ageing.
Think of your body like a car. Over time, even with regular maintenance, small parts start to wear out. Similarly, cells in the body get damaged. DNA mutations, faulty proteins, or worn-out cell parts like mitochondria are all examples of the damage that builds up with age. Our bodies try to repair this damage, but the repair systems aren’t perfect. Eventually, the damage becomes too much and affects how our body functions.
Some damage can be reversed, like protein clumps being cleared by certain processes. Others, like DNA mutations, usually can’t be undone. This helps explain why ageing continues even with healthy habits.
The Programmed Ageing Theory: A Built-in Clock?
Another idea is that ageing might be part of a genetic program. According to this theory, the same biological instructions that help us grow and develop might continue running even when they are no longer helpful. Over time, these processes may cause harm.
This is called “program-based” ageing. For example, some changes like shrinking of the thymus gland (which helps the immune system) or changes in hormone levels might be results of these internal programs going too far. Some scientists think that slowing down growth or development could delay ageing, as seen in animals with certain genetic changes.
Still, it's hard to prove whether ageing is really programmed or just the result of damage that adds up. It could also be a mix of both.
Can We Slow Down Ageing?
Understanding why we age matters because it can lead to ways to live longer, healthier lives. Some drugs, like rapamycin and spermidine, have been shown to extend lifespan in animals. These drugs may work by helping the body clear out damaged parts of cells or by slowing down certain processes.
Other drugs aim to remove harmful “senescent” cells, which stop dividing and start causing problems. These treatments are still being tested, and it’s not yet clear how effective or safe they are for people.
Interestingly, not all “anti-ageing” ideas work. Antioxidants, for example, once thought to slow ageing by fighting free radicals, haven’t shown strong results in studies with mice.
The Big Picture: It's Complicated
There may not be one single cause of ageing. It likely involves a mix of damage over time, genetic programs, and the body’s response to both. Some parts of the body may be more sensitive than others, and the ageing process may not look the same in every person.
One thing is clear: ageing isn’t just about wrinkles and grey hair. It affects our entire body at the deepest levels. Scientists are still working to sort out which changes actually cause ageing and which are just symptoms of it.
Final Thoughts
We still don’t fully understand why we age, but learning more about the theories helps us get closer to finding ways to stay healthy for longer. Whether ageing is due to wear and tear, a built-in program, or both, the hope is that one day we can slow it down—not just to live longer, but to live better.