Tired is a survivor hindrance that results from a lack of proper sleep or excessive physical labor.
When a party member is tired, their combat stats (strength, fitness, and shooting) take a temporary reduction, usually 3 or 4 levels to a minimum cap of -1, indicated by a flashing unhappy icon.
While scavenging, if a character expends their energy earlier than usual from swinging a weapon, a blue icon with an exasperated face will appear over them as a reminder. Tiredness will disappear once another day ticks over (assuming the character does not have trouble sleeping). This is indicated by the consumption of Food often accompanied by an Event.
Survivors with the Sound Sleeper trait will never suffer tiredness.