Not sure exactly what the drag coefficient of a human is, but astroconverter.com and azcalculator.com suggest an orbital decay time somewhere between 2 to 5 years.
Depends how hard you jump, and in which direction
I read the ISS orbits at about 8km/s so I assumed the speed of a few m/s jump in any direction would be negligible but I really have no idea
How about perpendicularly?
My thinking was if most of the momentum is going to be kept from the ISS, then jumping away or toward the earth would still follow about the same curve from the original ISS momentum with some decay from drag/not getting boosted, like if I was shrunk down and riding a bullet fired horizontally jumping up or down I think I’d still follow about the same path as the bullet
but if it’s going to take a really long time long months or years then maybe a small change at the beginning could have a big impact?
Perpendicular as in port/starboard or zenith/nadir?
First one, then the other.
But towards/away from the center of the gravity well is probably most interesting
I think jumping port/starboard would just change the inclination of your orbit.
Not sure if jumping zenith/nadir would change the height of your apogee/perigee, or the location. Maybe both?