Haze features a Hunger, Thirst, Fatigue (HTF) system that you must manage, or your character will experience adverse consequences. To check your character's current HTF ratings, use (speak) the !htf command in-game. Additionally, the system will periodically report your HTF as it degrades. Each of the three meters degrades at the same rate but is replenished by different actions. Further, a character's Constitution attribute rating can positively affect multiple aspects of their durability regarding HTF.
Hunger: Many different food items in the game will replenish your hunger rating at different rates.
Thirst: There are water sources littered about the island. Grab a canteen and have something to drink wherever you go!
Fatigue: There are a variety of bedrolls that offer a range of resting effectiveness. Limited resting locations, themselves, also provide various rates of recovery. Resting in heavy armor results in a penalty and will have lasting adverse effects.
HTF degrades at a rate of 10% per in-game hour (~27 real-life minutes). Upon logging out, the HTF system stores the timestamp and the next time it should run in real time. So, if you log out two minutes before HTF should tick down, it will tick down two minutes after the next time you log in.