I’ve done this when i was sleepy, if i have any mistakes, tell me.
In 3.0, if we took damage from anything, that could be fixed by using rags or bandages that can instantly heal you. IMO, in 4.0 we should have this:
When lost health by burning:
Bandage, then wait for 1-2 days to recover
When lost health by freezing:
Stay near a fire
Heatstim
When lost health cuz of blood loss:
Bloodbag + Bandage
Bandage, recover after (depends on your health):
If you lost 90% health by blood loss, recover after 1 day
If lost 45%, recover after half a day
If lost 20%, recover after 6 in-game hours
If lost 10% or less, recover after 1-3 in-game hours
When lost health cuz of falling:
Splint, but will make you move slower
(if it also caused bleeding) Bandage + Splint, that will also slow you down
When lost health by a zombie:
Antibiotics, vitamins, cough syrup, vaccine etc. anything that can lower your radiation
The terms we manage for the green bar are actually either Inmunity or infection.
Aside of that, we can assure that healing system will be overhauled in 4.x, as most of what you said here has already been discussed and it is planned to all this to be applied in a much more improved and realistic way.
I don’t think the blood/health bar represents how much of your total blood is remaining (with 0% being you have no blood left,) but rather 0% seems to be the point where you are incapacitated.