Why Do Astronauts Grow Taller in Space? The Secret Revealed

Why Astronauts Can Grow Taller in Space

No, they haven’t discovered a space stretching machine!

Imagine waking up one morning and discovering that you are suddenly a few centimetres taller. Your shoes feel smaller, your trousers look shorter, and your friends ask, “Did you grow overnight?”

For astronauts, something a little like this actually happens in space!

But before you start packing your bags for a space holiday, there is a catch: astronauts don’t really grow taller in space. Their bodies simply stretch because of what happens when gravity becomes much weaker.

What Happens to Your Spine?

Here on Earth, gravity is constantly pulling us down. This means the bones and soft cushions between the bones in our spine are gently compressed throughout the day.

These cushions are called intervertebral discs. They act a little like tiny shock absorbers, helping your spine bend, twist, and handle everyday activities.

In space, astronauts float because they are in a condition called microgravity. Without Earth's usual gravitational pull pressing down on their bodies, the discs between their spinal bones can expand slightly.

As a result, an astronaut's spine becomes a little longer. They can temporarily become around 5 centimetres taller while in space!

So, Do They Stay Tall?

Unfortunately for astronauts who were hoping to become basketball stars, the extra height doesn't last.

When astronauts return to Earth, gravity gets back to work. Their spinal discs gradually become compressed again, and their height usually returns to its normal level. This can happen surprisingly quickly after returning home.

Why Doesn't It Hurt?

The stretching itself isn't usually painful, but living in microgravity can cause other changes in the body. Muscles don't have to work as hard to support the body, and bones can lose some mineral density.

That's why astronauts spend around two hours a day exercising while aboard the International Space Station. Their workouts help keep their muscles and bones strong.

A Space Stretch Without a Yoga Mat!

Think of your spine like a stack of cushions. On Earth, gravity gently squishes the cushions together. In space, the squishing force is reduced, so the cushions have more room to expand.

So, if you ever become an astronaut, don't be surprised if you return home slightly shorter than you were in space!

Space may not have a magic growth potion, but it does have something almost as strange: gravity can temporarily change how tall you are. And the best part? You get to float while it happens!