their sense of balance doesn’t change
their sense of balance gets worse
their sense of balance gets better
lungs
stomach
legs and arms
torso and head
muscles
brains
legs
hands
it swells with fluid before shrinking
it speeds up
it slows down
nothing, it stays the same
microgravity
regular gravity
zero gravity
interacting
talking
eating
walking
motion sickness
food poisoning
migraines
sleeping sickness