* Hair Growth Cycle: Our hair goes through a cycle of growth, rest, and shedding. While some hairs are falling out, other hairs are actively growing. This creates a balance.
* Anagen Phase: The growth phase, called anagen, is the longest phase for most people. During this phase, the hair shaft grows continuously.
* Catagen Phase: The transition phase, called catagen, is a short period where hair growth slows down.
* Telogen Phase: The resting phase, called telogen, is when the hair detaches from the follicle and falls out.
* Exogen Phase: This is the shedding phase, where the old hair falls out.
Here's the important part: Even though hairs fall out, new hairs are constantly growing in their place. This means that while the hair shaft falls out, the hair follicle (where the hair grows from) remains intact and ready to produce a new hair.
Analogy: Imagine a field of wheat. Some stalks ripen and are harvested, but new ones are always growing. This keeps the field looking full even though some stalks are being removed.
Variations: It's important to note that the growth cycle varies depending on factors like genetics, age, and health. Some people have faster growth cycles than others.
So, to answer your question directly, our hair stays the same length because the hair growth cycle is constantly replacing falling hair with new hair, maintaining a relatively stable length.