Bodies in Space

Updated February 21, 2017 | Factmonster Staff

Have you ever wondered what happens to the human body after spending prolonged periods of time in space? The astronauts who spent weeks in Skylab learned that their bodies behaved differently in space than on Earth.


Astronaut in Space

Legs become thinner and thinner as time passes. The muscles of the legs push fluids and blood upward, which decreases the size of the thighs and calves.

Wasp Waist

The waist becomes smaller by 3 to 5 inches due to an upward shift of the internal organs.

Height and Posture

The body grows 1/2 to 21/4 inches taller because the spine lengthens and straightens. Relaxed body posture in space is head tilted backward, shoulders up (like a shrug) and arms afloat, up and forward with hands chest high.



Loose flesh rises, giving the face a high-cheekboned look. Bags appear under the eyes, veins in the forehead swell, and the whole face looks puffy.


At first the body feels lightheaded and nauseated, or sick to the stomach. After a few days these feelings go away, but a full-headed feeling (like hanging upside-down) remains.

Photo of astronaut Michael Hopkins courtesy of NASA

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