What do you think of this fact?
If you’ve always wanted to be a little taller, there’s one option: go to space. Sounds like a joke, but it’s well documented. According to NASA, astronauts on long missions grow up to 3 percent taller.
Your spine takes a break
On Earth, gravity presses down on your spine around the clock. In orbit, that pressure is gone. The skeleton stretches out and the spine gets longer. According to Wikipedia, the effect is complete after about a month, with a gain of roughly 1 inch.
For comparison: for someone who’s 6 feet tall, 3 percent is a bit over 2 inches. NASA already measured height gains of up to 3 percent on its Skylab missions.
Your seated height changes even more. A NASA report found about 6 percent growth in seated height, but only about 3 percent in overall stature. So not every part of the body stretches equally.
It’s only a loan
Back on Earth, astronauts shrink back to their normal height. And that isn’t always comfortable: many get back and abdominal pain while readjusting to gravity, because muscles and tissue could stretch freely in space.
NASA wanted to know exactly what’s going on back there. In one study on the space station, 6 crew members got spinal ultrasound scans at 30, 90 and 150 days into their flight. It was the first time anyone had used ultrasound to look at spine changes in space. They also had ultrasound and MRI scans on Earth before and after, for comparison.
Ultrasound has a big advantage for this kind of research: you can watch the body in motion, with no radiation involved.
A real problem for spacesuits and seats
For space agencies, this is more than a fun fact. Spacesuits, seats and workstations have to fit a body that changes shape in orbit. A suit that fits perfectly on launch day might pinch a few weeks later.
Nobody has figured out how to grow taller in their sleep. In orbit it works, just with a mandatory return policy.