Temporary height gain in weightlessness

In microgravity, the spine is unloaded, intervertebral discs expand, and spinal curvature changes. Astronauts therefore temporarily gain a few centimeters in stature; about 5 cm is an upper estimate, not a guaranteed increase for everyone. The change largely reverses after returning to Earth’s gravity. This is not bone growth, nor is it caused by a general absence of pressure throughout the body. [1–3]