Sleep

Sleeping restores fatigue and heals your wounds, so it's something you might want to do regularly.

Being under the effect of stimulants (coffee, Adderall, cocaine, etc) will make sleeping very difficult. You can consume those kind of items to purposely delay the need of sleeping.

Consuming Ambien, Cough syrup or Poppy sleep will increase your fatigue, and therefore help you fall asleep faster.

Lying down

The process of lying down in order to sleep.

To successfully sleep you'll need to reach a sleepiness above zero. That variable is checked when lying down, and it takes all these factors into consideration:

Penalties

• Suffering from sleeping pill dependance reduces it by 3
• Having the insomniac trait reduces it by 8
• Being under stimulants will reduce it by double the current stim level
• If your level of fatigue is below Tired (192 fatigue), it will be decreased by 1/4 of the value below 192

Bonus

• Being over a bed increases it by 5 points
• Being over a makeshift bed, seat or an extended cot will increase it by 4 points
• Being over an extended rollmat increases it by 3 points
• Being over a floor increases it by 1 point
• Being in any other kind of terrain will decrease it by the current movement cost of the terrain type.
• If your level of fatigue is above Tired (192 fatigue), it will be increased by 1/16 of the value above 192.
• Easy sleeper trait increases it by 8.
• Chloromorph mutation increases it by 10 when on dirt, a dirt mound or in a pit or by 5 on ash or grass, as long as there is no furniture on that tile.

Sleepiness will also be increased or decreased randomly by a small amount (+/-8) each time this check is done.

If sleepiness is above zero you'll start sleeping ("You fall asleep."), otherwise you'll stand up again ("You try to sleep, but can't...).

In addition to being sufficiently tired, you also need a comfortable enough temperature. The more bed-like your spot is, the more heat will be provided by it. This bonus heat will be used intelligently - it won't heat you above optimal temperature. It can't be used to cool down if it ends up negative.

• Furniture:
  • Bed (1000)
  • Makeshift bed, armchair, sofa (all 500)
  • Vehicle bed (300)
  • Vehicle bed & seat (250)
  • Vehicle seat (200)
  • Straw bed (200)
  • Fur rollmat, hay (all 0)
  • Mutations that grant thick fur ensure "furniture heat" doesn't drop below 0
  • Cot, improvised shelter, tatami (all -500)
  • Rollmat (-1000)
  • Everything else (-2000)
• Any torso and leg clothing with volume > 0.25 liters lying on the tile or located in vehicle cargo will help with heating: 60 * warmth * volume / 2.5 liters (will heat up all body, not just relevant parts)
• Mutations that give you fur will provide both the regular "clothing" warmth (regardless of if you want it or not) and this special sleep warmth that can only help

To compare those temperature values with clothing "warmth" values, divide by 60 (when it's too cold) or 30 (when too hot). When in doubt, drop any torso or leg clothing with volume >9.

Cooling down is harder. First off (obviously) remove warm clothing. Second, don't lie in the sun: +1000 and +500 for sunny and clear weather respectively. If it still isn't enough, skip few meals before going to sleep (-hunger/6).

Sleeping

Reduces fatigue and heals all body parts. Hunger and thirst increase more slowly when sleeping. Your sight range will be reduced to zero (simulating closed eyes).

The amount of healing you get depends on a few factors:

• Your current health.
• You heal quick with Fast Healer or Rapid Metabolism mutations.
• You heal quicker with the Very Fast Healer mutation.
• You heal very quick with the Regeneration mutation.
• If you are hibernating you heal extremely slowly.
• If you have a HP reducing mutation like Flimsy, Frail, or Fragile you heal slower. But only because your relative HP is lower.
• Broken limbs do not heal until mended.

You'll wake up when:

• Your fatigue is between 0 and -20 ("Fully rested.").
• There's a light source (such as the sun) and you've rested for a while ("The light wakes you up.").
• Your body temperature is low/high ("The cold/heat wakes you up.").
• You cough - 1/10 chance if it's regular coughing (like from common cold), 1/3 if it can harm you (like from heavy smoke)
• You hear a sound (sound volume > sound distance to you). Effective volume is lowered by 3d15 if you have Heavy Sleeper.
• Your alarm beeps. Alarm is equivalent to sound of volume 12 (20 if from a bionic) going off at your location. If that doesn't wake you up, alarm will keep repeating every 10 minutes until you wake up.
• Your pain counter increases.