Health

Health represents how much damage an entity can sustain before becoming incapacitated. Warframes, Kubrows, Kavats, and Rescue targets will enter "bleedout" upon running out of health, while all other entities will be killed. A Warframe's health is indicated as a red number at the top right of the screen. The health of other entities can be displayed over their heads, should the player aim directly at them. While a Warframe is losing health, the screen's edges will begin to flash red at a pulse. Once the Warframe reaches 10% health or below, a loud, heartbeat-like sound will play, and a slight ringing can be heard. This sound also plays when bleeding out and when dead.

Most attacks will only damage health after the entity's shields have been fully drained, but there are a few exceptions. damage, which is commonly dealt by units like Toxic Ancients, Toxic Crawlers and Venomous Eximus, will bypass shields and strike the target's health directly, which can also proc a damage-over-time effect. procs, such as those dealt by Grineer Powerfists, will temporarily halve victim's health (both current and maximum) even if the attack itself is absorbed by shields. Finishing damage, such as from the Bleed status effect (from damage), will also bypass shields.

Health Classes
There are different types of damage which deal reduced or increased numbers against different entities. MOAs, for example, are mostly metal in composition and are not as easily cut open as the flesh of living Crewmen. Hence, MOAs have Robotic health, while Crewmen have Flesh as their health type; effects deal penalized damage to Robot health and bonus damage to Flesh.

There are thirteen health classes in total, but two of them are reserved for shields only and two of them are reserved for armor only&mdash;these four act differently from health, and are covered on Shields and Armor pages. The remaining nine health classes are partitioned into the three standard Factions, though both the Corrupted faction and the Tenno themselves borrow from these.

The fact that Cloned Flesh differs from Flesh and that both Corpus and Tenno have the latter implies that Tenno are as human as the Corpus, while the Grineer are imperfect replications. Relevant to game mechanics, these two types of health share most vulnerabilities and all resistances, except that cloned flesh is flammable while normal flesh is easily  poisoned.

Infested is different from Infested Flesh, even if by name they would seem identical. While you can check the details on their respective pages, know that both are vulnerable to the same types of damage, just resistant to different types; you can most likely use the same weapon loadout to perform against either type.

Healing
Unlike shields, health does not naturally regenerate over time, except when the Rejuvenation aura mod is equipped by at least one member of the cell. Otherwise, damage inflicted upon health must actively be healed either by picking up a Health Orb (and Energy Orbs with Equilibrium) or directly by a few certain Warframe abilities. Trinity and Oberon are the two Warframes with an inherent ability to explicitly restore health to all Warframes within the cell, and Nekros can Desecrate nearby corpses for a chance to spawn more health orbs. A Chroma in can raise both players' current and maximum health temporarily with Elemental Ward, and when the effect runs out, only the maximum health returns to its original value; effectively, the affected players have restored that much health. Additionally, Inaros's Scarab Swarm ability is capable of healing allies that are near enemies being affected by the ability.

Warframe Abilities
Aside from the above abilities, Nyx is able to use Mind Control on Corrupted Ancients, enemies which can heal surrounding allies. Somewhat similarly, if a Nekros slays a Corrupted Ancient, it can be resurrected on the side of the Tenno by his ability, Shadows of the Dead.

Ability Augments
If Limbo has Haven or Hydroid has Curative Undertow installed, either one can act as a healer for the entire cell. Pool of Life increases the healing capabilities of Trinity's Well of Life power. Finally, Saryn can heal herself personally if she equips Regenerative Molt, reducing the burden she might place on their allies or else enabling her to solo better.

Equipment
There are some items that can be used in a mission to heal lost health.

Weapon Mods
There are PvP-only mods that allow for players to regain health based off their combat performance, and Syndicate-purchased mods that restore health after gaining enough affinity to meet the necessary thresholds. Lastly, Life Strike will restore health to the Tenno as a percentage of damage inflicted by the equipped melee weapon.

Bleedout & Death
When health is reduced to 0, Warframes enter the Bleedout state. In bleedout, Warframes can barely move and are restricted to firing their sidearm. If they do not receive the appropriate attention from an ally within 20 seconds, they are killed in action. It is quite difficult to complete missions successfully when all players are dead, so players typically strive to keep health above 0 at all times.

Effective Health
Damage calculations get complicated when damage resistances are involved. Effective health is a common metagame concept which states that because each hit point you have actually absorbs more than one point of damage, you effectively have more hit points than indicated. In WARFRAME, effective health can be increased by armor, resistance mods, and health classes.

For example, if your Warframe has 300 health, and you are being attacked by an enemy that deals damage:
 * 1)  attacks deal 25% less damage to Flesh health. If they would normally strike for 100 damage in a single attack, they would only deal 75 damage to your Warframe.
 * 2) Therefore, to deal 300 damage to your Warframe, they would have to output 400 total points of damage.

In reference to damage, your Warframe has 400 effective health even though it has only 300 nominal health. Effective health can only ever be considered in the context of damage, because its value depends on the bonuses and penalties of the incoming damage as much as it does on the resistance values of your armor, mods, and health. Depending on how you build your Warframe and use its abilities, you can experience a drastic difference in survival between different types of enemies. (A specific build of Valkyr has been shown to have ~3800 effective health against most Grineer but only ~850 effective health against typical Corpus enemies.)

Effective health is a valuable metric because it allows you to compare different forms of survivability.