Health
This article is timeless and should be accurate for any version of the game.
Soldiers' Health
Foxhole uses a diegetic feedback system: there is no visible health bar, instead the game shows the player's health visually. When a player is hit, blood will appear on their character model. Depending on how much HP they have left, blood will range from minor to severe. To replenish your health, another player must use a First Aid Kit on you to restore your HP to 100%.
Although it's not visible, a soldier has 100 HP.
Bleeding 
Whenever a player is hit (for more than 25 damage) there's a chance the Bleeding status is applied to them which means they are now slowly losing their health. A blood drop icon appears below your stamina bar if you are bleeding. If you see blood spew off a soldier, it means that they are bleeding. The health loss rate is always 1hp per second meaning a bleeding player will die in less than 100s. Shrapnel damage always applies the bleeding status.
You can stop your own bleeding by using a Bandage on yourself to stop the bleeding, but it won't heal you. Using a First Aid Kit on someone stops their bleeding on top of healing them. If you bleed for too long, you will become wounded.
Wounded and the Death Timer
When a soldier is hit by Light Kinetic, Heavy Kinetic, or Shrapnel damage and their health gets below 0 HP they become wounded. They collapse on the ground and a 30s death timer starts. If they are not revived with a Trauma Kit by the end of the timer, they will die. The Wounded Player can be picked up by pressing E to be carried on your shoulder to be moved to safety, the soldier's death timer is stopped when carried and starts again when dropped. The wounded player gets the options to "give up" after 10 seconds of being downed or if someone is carrying them, press E to give up to go immediately to the respawn screen. Giving up as soon as possible won't make you respawn faster than if you wait for your death timer to end (time spent injured is substracted from respawn timer).
A Wounded player is killed if they get hit.
Damage types other than Light Kinetic, Heavy Kinetic, and Shrapnel can never result in a wounded player, they just die instead.
You can't return to the Home Region while wounded.
Critically Wounded Soldier
When a wounded player's death timer reaches zero or they give up, the player dies but there's a small chance they will leave behind an item called a Critically Wounded Soldier. This item looks like a wounded soldier on the ground except the soldier isn't bloody and is resting on its side. It can be picked up by pressing V and is carried on the shoulder, just like the Wounded Player. It can be brought to a Hospital or Field Hospital to be converted into Soldier Supplies.
Fall Damage
Falling from a high enough place can hurt or outright kill you. This only applies if it's from a height higher than 6 or 7 meters.
Drowning
If you run out of stamina while swimming in water, you will drown. A full stamina bar will always give you exactly 16s of swimming time (Standing still in water does not use stamina).
Stun
Receiving any kind of damage will stun you, which makes you slower for a few seconds. The strength of the slowdown scales with the amount of damage received. Hits dealing less than 25 hp cause no stun.