Health System

As with most first person shooter games, the player has a health system in the Call of Duty series. The Damage Multiplier mechanic plays hand-in-hand with the health system. Some weapons are an instant kill, namely headshots from higher-powered weapons, shotgun blasts within a certain range, most killstreak weapons, explosives within the lethal blast radius, rocket launchers/grenade launchers in the lethal blast radius, the Knife, most melee attacks, some special weapons, like the Crossbow, Ballistic Knife, some specialist weapons, and the throwable melee weapons, like the Tomahawk, Combat Axe, Throwing Knife or the Spike Drone. Large falls or "death zones" can instantly kill players, regardless of how much health they have.
==Overview==
In all games before Call of Duty 2 and Call of Duty: WWII’s campaign mode, the player needed to pick up health kits in order to regain health. Starting with Call of Duty 2, health kits were removed in favor of a regenerative health system. Whenever the player is below 33% of their maximum health, tunnel vision or a red tinge (depending on the game) will appear on screen, accompanied by a raised heartbeat and strained breathing. In Hardcore, health regeneration is disabled, and maximum health is reduced to 30 points. In Old School, health regeneration is also disabled, and the player's maximum health is increased to 200.
Controlling most vehicles either through various single player sequences or through killstreaks will not have natural health regeneration.
==Call of Duty 4: Modern Warfare==
In Call of Duty 4: Modern Warfare, if the player is above 55 health of the total 100, all health is instantly regenerated after 5 seconds since the player was last damaged. If the player is at or below 55 health, and after 5 seconds since the player was last damaged, health will regenerate in chunks of 10 every 0.05 seconds until he gains maximum health or the process is interrupted by damage. The Juggernaut (Perk) gives the player a 25% damage reduction from all sources of damage, except for instant-kill weapons, the Knife, falling damage and death zones that instantly kill players. This makes nearly every weapon in the game require 1-2 shots more to kill a Juggernaut player. Stopping Power is a direct counter to this, making all damage from bullet weapons the user fires do 40% more damage compared to normal damage values, reducing the shots needed to kill players not using Juggernaut by 1-2 shots. Juggernaut and Stopping Power cancel out eachother, and Juggernaut cancels out Sonic Boom, a perk that increases all explosive damage by 25%. All these same effects apply to Call of Duty: Modern Warfare Remastered.
==Call of Duty: World at War==
In Call of Duty: World at War, if the player is above 55 health of the total 100, all health is instantly regenerated after 5 seconds since the player was last damaged. If the player is at or below 55 health, and after 5 seconds since the player was last damaged, health will regenerate in chunks of 10 every 0.05 seconds until he gains maximum health or the process is interrupted by damage. 
The Juggernaut (Perk) gives the player a 25% damage reduction from all sources of damage, except for instant-kill weapons, the Knife, falling damage and death zones that instantly kill players. This makes nearly every weapon in the game require 1-2 shots more to kill a Juggernaut player. Stopping Power is a direct counter to this, making all damage from bullet weapons the user fires do 40% more damage compared to normal damage values, reducing the shots needed to kill players not using Juggernaut by 1-2 shots. Juggernaut and Stopping Power cancel out each other, and Juggernaut cancels out Sonic Boom, a perk that increases all explosive damage by 25%. The Flak Jacket perk allows the player to take less damage from explosions, which also cancels out Sonic Boom.
In Zombies, purchasing the perk Juggernog increases the player's health to 250.
==Call of Duty: Modern Warfare 2==
Starting with Call of Duty: Modern Warfare 2, blood replaces the tunnel vision effect and gradually appears as the player takes damage. A player can tell when their character has successfully regenerated their health by an exhaling sound. The Juggernaut (Perk) has been removed in this game, Stopping Power returns, making all damage from bullet weapons the user fires do 40% more damage compared to normal damage values, reducing the shots needed to kill players by 1-2 shots.
==Call of Duty: Modern Warfare 3==
In Call of Duty: Modern Warfare 3, if the player's health is below 100, after 5 seconds of not receiving damage, health regenerates at a rate of 1 every 0.05 seconds. The Support Strike Package introduced Ballistic Vests, which absorbs 50 damage before it is depleted, the last shot on the vest can absorb 50 additional damage in core modes, effectively giving the vest a range of 50-100 HP increase. When using a Juggernaut, a player will only take 8% of all normal damage. Essentially, this means the player will have 1250 health points while in a Juggernaut suit. However, only the Juggernaut Recon regenerates health in this game; the regular Juggernaut (Killstreak) does not, for balancing reasons.
In Survival Mode and Special Ops Chaos, Body Armor essentially gives the player extra health, which can absorb additional damage to the player. Body armor cannot be regenerated naturally, however. It can only be restored by purchasing a new set of body armor.
==Call of Duty: Ghosts==
In Call of Duty: Ghosts, a Resistance Perk called ICU halves the entire duration of a player's health regeneration time. A critically injured player can effectively regenerate to full health in less than 5 seconds. As before, the Ballistic Vests gives players 50-100 more health upon use. The three different types of Juggernaut suits all give a massive health boost/damage reduction to the player. The Juggernaut Recon, Maniac and the regular Juggernaut (Killstreak) do not regenerate health at all, compared to the previous version of the Juggernaut Recon. The same mechanics apply with the Field Order rewards that turns players into other special characters, such as Michael Myers, the Predator and Death Mariachi.
In the Extinction mode, the health is represented by a bar in the bottom left corner of the screen, but still works pretty much the same, although health regeneration is slower. The Tank class can upgrade themselves to have an increase in health. This can be sped up through various ways such as Medic class upgrades. As with Body Armor in Modern Warfare 3 survival mode, Armor in Extinction allows the player to endure more damage than normal, and it can be upgraded to withstand even more punishment.
==Call of Duty: Advanced Warfare==
If Paintball Effects is turned on, the blood on the player's screen indicating they are damaged will be replaced with yellowish-green paint. The XS1 Goliath robotic Juggernaut-like suit gives the player hundreds of more health, though not nearly to the same degree a Juggernaut suit does. 
==Call of Duty: Black Ops III==
In Call of Duty: Black Ops III’s campaign mode, the Realistic difficulty reduces the player's health to a miniscule, effectively making every shot or explosion received lethal. In Zombies, players now have 150 health by default, making the game slightly more forgiving to mistakes. Instead of going down in two hits, players can now survive two, going down on the third. As with previous Zombies titles, purchasing Juggernog will give the player increased health; it now gives the player the ability to survive four hits, going down on the fifth.
==Call of Duty: Infinite Warfare==
In Infinite Warfare, Nano Shots can be used to drastically speed up the health regeneration process. One of the Merc combat rig Payloads is Reactive Armor, which heavily decreases the player-caused damage from all sources barring environmental damage. While the payload is active, the player's health is also increased to 114 (133 in earlier updates). Synaptic's Reaper and Rewind payloads regenerate the player through various ways, though while the Reaper payload is active, the player cannot regenerate health.
The Specialist and #YOLO difficulties in the campaign reworks the health system, as it tracks various injuries which can disable or impede the player's functions. Natural health regeneration is disabled throughout these difficulties (except certain sections such as Jackal sections), Nano Shots must be used to heal additional health and restore various limbs. Getting shot at the head will result in an instant kill or slow death via suffocation, wearing a helmet will prevent these from happening.
Health in Infinite Warfare Zombies is represented by the player's portrait at the bottom left of the screen, getting damage will make the portrait progressively bloodier until the player regenerates health.
==Call of Duty: WWII==
As mentioned earlier, Call of Duty: WWII’s campaign mode disables natural health regeneration. The only way the player can restore additional health is to find additional first aid kits throughout the level or request one through Zussman's squad ability if he is available. Health is represented through a bar in the bottom left of the heads-up display.
In multiplayer mode and Nazi Zombies mode, the health system functions similarly to the previous games. Both the Remedy basic training and Commando Division level 2 abilities allow faster regeneration (though having both will conflict and cancel the Remedy effects). Killing enemies in Commando level 2 will also trigger immediate health regeneration. Throwback Moshpit reintroduces the Juggernaut perk, allowing the player to take more damage.
In Nazi Zombies specifically, both health regeneration and maximum health can be manipulated through various abilities. Geistschild allows the player to survive hits that are considered fatal regardless of the amount took.
==Call of Duty: Black Ops 4==
In Call of Duty: Black Ops 4, the health system is reworked, with all players having a default of 150 health. In Multiplayer, players can use a health pack to instantly start their healing process, however this ability has a short cooldown. The cooldown of the health pack can be reduced by equipping Stim Shot in the player's loadout. 
This change encourages a more tactical flow to the gameplay, where all players must heal themselves before and after each combat engagement. As there is no campaign in Black Ops 4, this new healing system is only in Multiplayer and Blackout. There is also a specialist weapon exclusive to Crash called the TAK-5 which can instantly boost the health of his teammates.
The Blackout battle royale gamemode requires players to find health kits around the map, as natural regeneration is disabled.
As the Perk-a-Cola system was reworked in Black Ops 4 Zombies mode, which makes Juggernog is no longer available, the only way to change player maximum health is to play on lower difficulty levels. Casual difficulty allows the player to start at 250 health, though higher difficulties up to Realistic reduces the health to 50.
==Call of Duty: Mobile==
In Call of Duty: Mobile, the health system has the classic 100 default health. Perks like Fast Recover and Quick Fix that helps the regeneration process. While using a XS1 Goliath, the player will have 750 health points, but natural health generation is disabled.
In Battle Royale prior to Season 8 2021, players can pick up adrenaline stims in order to increase the maximum health capacity to 150. After the update, the health system is reworked, being mostly the same as Warzone, players can pick up armor plates to protect up to 150 points of damage. Using an overcharger will increase the armor points up to 200. Armor does not regenerate naturally.
In Zombies mode, every player starts with 100 health points (150 if one of the teamates have Medic Module equipped). Drinking Juggernog increase health by 100 points. The players can also buy armor from the vending machine to increase armor to the maximum of 150 armor points, but Armor does not regenerate naturally.
==Call of Duty: Modern Warfare ==
In Call of Duty: Modern Warfare, the health system has returned to the classic 100 default health, though Stim Shots can be used to drastically speed up the health regeneration process. There's also a new perk called Quick Fix that will speed up the player's health regeneration while capturing objectives, and restores a part of the player's health upon killing an enemy with a weapon (excluding Killstreaks). The Juggernaut (killstreak) reappears in the title, with a colossal amount of health compared to its predecessors, though as with Ghosts and the Modern Warfare 3’s regular juggernaut, health regeneration is disabled and the visual indicator of decreasing health on the perspective of the juggernaut will have cracks on the visor.
In Operations, armor can be used to endure more damage than normal, as with the previous games featuring armor. In Warzone, armor can be used as extra health, protecting up to 150 points of damage in addition to the 100 points of health. It can only be regenerated by finding more armor plates, and a maximum of three armor plates can be used all at once. Finding a new armor plate while wearing a damaged one will replace the damaged armor plate with a new one, instead of stacking the additional armor health.
Exclusive to the campaign, taking critical damage will make all colors on the screen set to greyscale, only to turn back to color after recovering health. This was initially included in multiplayer before the game's release, but it was removed following player feedback.
==Call of Duty: Black Ops Cold War==
In Call of Duty: Black Ops Cold War, the health system is identical to Modern Warfare, however the health is at 150.
==Call of Duty: Vanguard==
In Call of Duty: Vanguard, the health system is once again identical to Modern Warfare.
==Call of Duty: Modern Warfare II==
In Call of Duty: Modern Warfare II, the health system functions like in Vanguard.
==Call of Duty: Modern Warfare III==
In Call of Duty: Modern Warfare III, the health system functions like in Black Ops Cold War with the health sitting at 150.
==Gallery==
Blood Splatter CoD2.jpg|The player critically damaged in Call of Duty 2.
Blood Splatter CoD4.jpg|Damaged in Call of Duty 4.
Blood Splatter WaW.jpg|Damaged in Call of Duty: World at War.
Blood Splatter MW2.jpg|Damaged, in Call of Duty: Modern Warfare 2. The tunnel vision effect was replaced with blood.
Blood Splatter BO.jpg|Damage in Call of Duty: Black Ops.
Blood Splatter Survival MW3.png|Damaged in Call of Duty: Modern Warfare 3. Along with blood, dirt covers the player's screen.
Blood Splatter BOII.png|Damaged in Call of Duty: Black Ops II.
Blood Splatter CoDO.png|Damaged in Call of Duty: Online
Blood Splatter CoDG.jpg|Damaged in Call of Duty: Ghosts.
Blood Splatter AW.png|Damaged in Call of Duty: Advanced Warfare.
Paintball Effects on HUD AW.png|The paintball effects on the HUD indicating the player is damaged when Paintball Effects is on in Call of Duty: Advanced Warfare.
Blood Splatter BO3.png|Damaged in Call of Duty: Black Ops III.
Category:Game Terms
Category:Gameplay mechanics