It's the equivalent of decompression when you are underwater. You don't want the astronauts to get sick from gravity and stuff.

Interesting

Or deep-water scuba-diving.

Decompression sickness (DCS; also called divers' disease, the bends, aerobullosis, and caisson disease) is a medical condition caused by dissolved gases emerging from solution as bubbles inside the body tissues during decompression. DCS most commonly occurs during or soon after a decompression ascent from underwater diving, but can also result from other causes of depressurization, such as emerging from a caisson, decompression from saturation, flying in an unpressurised aircraft at high altitude, and extravehicular activity from spacecraft. DCS and arterial gas embolism are collectively referred to as decompression illness.

(Disclaimer: I learned about The Bends on Flipper in the Sixties when Sandy had a bad case of them.)

and LOL for Flipper 😀

I guess an anti-gravity bed might help.

Looking now.

https://www.space.com/microgravity-vision-effects-astronauts

The eyes have it! Scientists focus in on how microgravity changes astronaut vision

By Leonard David published April 2, 2023

After decades of collecting data about how astronauts' vision is affected by spaceflight, scientists have identified a set of microgravity-induced changes to the human eye known as Spaceflight-Associated Neuro-Ocular Syndrome, or SANS. This condition is considered a risk to human health in long-duration spaceflight.

…

Overall, clarity over vision issues in space has come a long way since the February 1962 flight of Mercury astronaut John Glenn. That first three-orbit spaceflight by an American had Glenn dutifully monitoring his vision by reading an eye chart to see if his eyeballs might change and alter his vision.

… more …

(Something I never thought of.)