Unlike zombies, the player and other survivors need to sleep. However, this mechanic can be disabled in multiplayer settings at will, and is disabled by default multiplayer (but can be tweaked to the player's liking). When the player needs to sleep, the tired moodle will show up on the screen. To sleep, the player needs to find a bed, sofa, or other chair. Or, if the player is tired enough, even the floor will do. A player can also sleep in a tent or vehicle.
Failing to sleep will cause the player's damage when using weapons to drop. The player's field of view will also decrease, in addition to several other effects. The player cannot die from lack of sleep, though and can't currently fall asleep due to sleep deprivation.
There are many factors affecting how long the player will need to sleep for, including fatigue level, bed quality, character traits, stress, and pain.
The player typically requires between 6 and 12 hours of sleep per night. If the player hasn't slept for a long time, the sleeping time can drastically increase depending on the severity of the exhaustion.
If there is no extreme situations (e.g., sleeping regularly every day), players need to sleep:
- ≈9 hours a day.
- ≈6 hours a day if Wakeful trait is selected.
- ≈12 hours a day if Sleepyhead trait is selected.
Sleeping time can be induced by using sleeping tablets. Sleeping tablets can also induce the need to sleep when the player is otherwise unable to (e.g., experiencing pain).
Sleeping time can be reduced by using vitamins.
The player cannot sleep for fewer than 3 hours and will wake up after a maximum of 16 hours, even if they aren't fully rested.
Effects of sleeping
While sleeping, time will fast forward until the player wakes up. Tiredness will slowly disappear and the effects of sleeping tablets and beta blockers will be removed. Sleep will also take away the player's panic.
Sleeping on a bed of "average" or "poor" quality (or the floor) will reduce the rate at which tiredness disappears, and the player will wake up without being fully rested while also being potentially sore in the neck.
Waking up at night
During sleep, the character's vision is blocked out and they cannot see what is going on in the outside world. Nearby sounds (such as zombies smashing down doors or windows) may awaken the player if they are loud enough or close enough. One use of this mechanic is to use an alarm clock to wake the player up at a specified time to help enforce a consistent sleeping schedule.
If the player does not wake up due to the noise from a zombie entering their base, they will not wake up until the zombie deals damage. The player can also be awoken by extreme hypothermia/hyperthermia or if the vehicle they are sleeping in is attacked.
A player can also wake up due to a nightmare. There is a base probability of 5% of having a nightmare, but the probability increases the more stressed the character is. A nightmare can be distinguished from zombie invaders or external noises by an increase in the stress moodle, whereas zombie invaders will not cause added stress.
When indoors, sheets/curtains should be on and closed for all surrounding windows and doors, which should be shut to ensure a secure rest. When outdoors, the character should try to look for shelter. If there is no shelter and sleep is required, the character should set up a tent somewhere relatively safe, where the risk of nearby zombies is low.
If the sleeping event sandbox option is set, the player can be woken up in a panic by nearby zombies entering through nearby unsecured doors or windows. The probability increases when doors/windows are left open or unbarricaded, the lights are left on, a refrigerator or freezer is nearby and powered, or devices (stoves, radios, TVs) left on.