The Biology of Aging: How Cellular Damage and Repair Shape Lifespan.
Aging is not something you can watch happening. It doesn’t arrive in a clear moment, and it doesn’t move in a way that draws attention to itself. Most days feel the same as the ones before them. Your body responds, your mind keeps up, and everything feels familiar enough that you don’t question it. And then, at some point, without trying to notice it, you do. Something small feels different. Aging started much earlier. Inside your body, there’s constant activity, even when you feel completely still. Cells are always at work fixing damage, replacing parts, and building what’s needed to keep everything running. DNA is copied again and again. Proteins are made, used, and cleared away. Old cells are removed, and new ones take their place. For years, this system keeps things balanced in a way that feels almost effortless from the outside. Damage happens, but it doesn’t stay. Every day, your cells deal with small amounts of stress. Some of it comes from the world around you like sunlight, po...