It represents the tiredness a survivor is feeling. Fatigue rises as survivors perform actions, like scavenging or travelling. While a fatigue of 100% will not stop a survivor from performing some actions like travelling, it will make him/her more vulnerable to injuries.
Fatigue increases at a determined rate when scavenging, and rises every time a survivor moves from one zone to another. The level of fatigue a survivor gets from moving depends on the weight of the items they are carrying. A survivor with half their carrying capacity will get more fatigue than a survivor with no items, and a survivor with their capacity at its limit will get fatigue even faster. A survivor carrying more items than their total carrying capacity will get very harsh fatigue penalties. Fatigue recovers when survivors are left to rest in safehouses. Recovery time can be speed or by developing certain skills like Insomniac. Some Infocards have an effect that reduces fatigue increase or that speeds up recovery time.
Fatigue can immediately be reduced by 40% by using Amphetamines which can be purchased with NECRA Credits.