|"I want the burn of smoke and nicotine in my lungs. But all I feel is the Sentinel Health System automatically counteracting the damage. Even self-destruction's no fun anymore."|
|— Adam Jensen|
The Sentinel RX Health System is implanted in the chest, and apparently, improves the user's short-term health by sealing lacerations and bullet wounds, stopping blood loss, releasing adrenaline and morphine and setting broken bones when necessary. Much like basic arm and leg prostheses, the Sentinel RX does not require extra energy cells to operate; rather, it runs off of normal biological electricity, though it does take several seconds to function.
In-game, the player normally has a default of 100 out of 200 health points. Once the player takes damage, this number will decrease, and it will automatically recharge to 100 if the player does not take damage for a substantial period of time. Ingesting some items, such as Beer will recharge a definite amount of health immediately, and if the health meter is at 100, they will increase it past that point to a maximum of 200. However, the health bar must be at 100 to get a boost (For example, if the player has 97 health, Beer will only increase it to 100, and if they are at 100 it will grow to 105).
The Sentinel RX Health System is already fully upgraded at the beginning of Back in the Saddle.