Astronauts come home taller
Without the daily load of gravity the spine lengthens. Astronauts gain a few centimetres in space and lose them again after landing.
Established2 min read
Skylab measurements found increases in height of a few centimetres, from unloading of the intervertebral discs and a shift of fluids. Later crews have shown the same pattern. The gain is not bone growth. It is the spine, no longer squeezed, taking on fluid and expanding.
It is uncomfortable. Stretched ligaments and a changed posture contribute to the back pain common in flight. After return, the height leaves over days, the way a morning height leaves by evening, only from a larger start. Suits and seats have to be designed for a slightly longer person than the one who launched.
Caveats
- A few centimetres is the range, not a guaranteed increment for every astronaut.
- The gain is temporary. Nothing about space makes a person permanently taller.
Sources
- 1Thornton W. E., Hoffler G. W., Rummel J. A.. Anthropometric changes and fluid shifts. Biomedical Results from Skylab, NASA SP-377, 1977.