Survival needs

Hunger and thirst

Both needs run from 100% down to 0%. The table shows how fast each one drains and how long a full bar lasts if you never sprint.

When either need reaches 0% you lose 3 health every 10 seconds until you eat or drink, and it will kill you.

Sprinting multiplies both drains by 2. Fever, shivering and gut illness add to them, and cooking skills slow them.

Keeping both needs at 40% or more lets your body fight a low infection. Letting either one fall under 15% makes the infection spread 1.5 times faster.

Body temperature

Your body temperature drifts up or down whenever the temperature you feel is outside the comfortable range. The table lists the body temperature at which each state begins.

You hold a steady body temperature while the temperature you feel, after clothing, wind and wetness, stays between 12 °C and 29 °C.

Every point of wetness makes you feel 0.12 °C colder, wind makes wet clothes colder still, and soaked clothing loses 50% of its warmth.

Indoors counts as 18 °C and a vehicle with the engine running as 21 °C. A tent or a roof is worth 3 °C in the cold, and shade is worth 7 °C in the heat when the sun is out.

In the heat a drink cools you by 4 °C for 2 minutes, and only 25% of your clothing's warmth counts against you.

The air gets 6.5 °C colder for every 1,000 m you climb, and mountains above 250 m cool 2.5 times faster than that.

Bare hands or feet in a wind chill of -10 °C or lower get frostbite after 4 minutes.

Warmth from everyday clothing

Every part of your body that is covered adds warmth, whatever the garment is. The numbers are degrees added to the temperature you feel.

Fully dressed with a hat you gain 12.5 °C. Named garments in the next table add their own warmth on top of this.

Warm, cool and rainproof gear

Named garments and gear change the temperature you feel while you wear them. A negative number keeps you cooler, which helps in the desert.

Item	Worn on	Warmth	Rain kept off	Scent
Coyote Fur Parka	Outer layer	5.5 °C
Shearling Coat	Outer layer	5 °C
Winter Parka	Outer layer	5 °C
Lion-Skin Cloak	Outer layer	3.5 °C		x0.9
Hand-Knitted Sweater	Outer layer	3 °C
Insulated Overalls	Legs	3 °C
Patchwork Duster	Outer layer	3 °C	40%	x0.95
Fur Hat	Head	2.5 °C
Hazmat Suit	Outer layer	2.5 °C		x0.6
Snow Pants	Legs	2.5 °C
Buckskin Jacket	Outer layer	2.2 °C
Trapper Boots	Feet	2.2 °C	30%
Leather Jacket	Outer layer	2 °C
Thermal Base Layer	Base layer	2 °C
Winter Boots	Feet	2 °C
Patched Jacket	Outer layer	1.8 °C
Fur-Lined Gloves	Hands	1.5 °C
Lined Hoodie	Outer layer	1.5 °C
Scent-Blocker Suit	Outer layer	1.5 °C		x0.55
Sleeping Bag	Carried roll	1.5 °C
Patrol Vest (IIIA)	Armor	1.2 °C
Storm Shell	Outer layer	1.2 °C	90%
Wool Beanie	Head	1.2 °C
Ash Shroud	Outer layer	1 °C		x0.7
Concealable Vest (II)	Armor	1 °C
Ghillie Suit	Outer layer	1 °C		x0.8
Modular Plate Carrier	Armor	0.9 °C
Balaclava	Face	0.8 °C		x0.95
Bedroll	Carried roll	0.8 °C
Brushwood Poncho	Outer layer	0.8 °C		x0.9
Concealable Vest (IIA)	Armor	0.8 °C
Rain Poncho	Outer layer	0.8 °C	70%	x1.05
Riveted Leather Vest	Base layer	0.8 °C
Wool Gloves	Hands	0.8 °C
Crate-Wood Armor	Armor	0.7 °C
Cargo Pants	Legs	0.6 °C
Combat Boots	Feet	0.6 °C
Silent Treads	Feet	0.6 °C
Slick Plate Carrier	Armor	0.6 °C
Tarp Poncho	Outer layer	0.6 °C	60%
Charcoal Scarf	Face	0.5 °C		x0.85
Combat Helmet	Head	0.4 °C
Riot Helmet	Head	0.4 °C
Snow Goggles	Eyes	0.4 °C
Tactical Gloves	Hands	0.4 °C
Rag Foot Wraps	Feet	0.3 °C
Boonie Hat	Head	-0.8 °C

Scent multiplies how far the infected can smell you, so a number under 1 hides you and a number over 1 gives you away.

Hours awake

Your body keeps its own clock of hours awake, which runs much faster than real time. The table shows what happens as the hours add up.

One real minute awake at a walking pace adds 6 body minutes. Hard work counts for up to 1.6 times that, standing still for as little as 0.4 times, sitting by a fire counts for 0.5 times and the small hours of the night add 20%.

Between tired and the worst stage, the delay before your first shot grows from 120 to 380 ms and you lose 25% to 55% of your stamina recovery.

The chance of nodding off grows from 8% to 45% per minute. It is 1.5 times as likely while driving and 1.2 times as likely standing still, and you are gone for 0.8 to 2.2 seconds.

Caffeine hides 6 hours of tiredness while it lasts and makes nodding off 75% less likely, but it never clears the hours and it spoils your sleep.

The most your body can go without sleep is 48 hours.

Sleep quality

How well you sleep decides how fast the hours awake are cleared. Quality depends on the surface, shelter, warmth, safety, rain, noise and whether someone keeps watch.

While you sleep, 5 body minutes pass every real second, so 10 hours of sleep take two real minutes. A night never runs longer than 14 hours.

Sleep will not come until you have been awake for 4 hours, and the first 12 real seconds must pass before any of it counts.

6 hours of decent or good sleep leave you well rested for 60 minutes.

An infected within 22 m wakes you. With someone keeping watch you sleep deeper and only wake when one is within 12 m, because the watcher sees them coming from 45 m and wakes you.

Logging off in your own bed or inside your own base clears 2.4 hours awake for every real minute away. Logging off in the open clears only 0.2 hours per minute and never takes you below 8 hours awake.

Where you can sleep

Every place to sleep starts with a comfort score, and a higher score gives better sleep. Shelter, warmth and a safe base raise it, while cold, rain, nearby infected and caffeine lower it.

Place	Starting comfort	Keeps you warm
Bare ground	0
Vehicle seat	0.5
Bare ground with a Bedroll	0.7	No
Bare ground with a Sleeping Bag	1	Yes
Old mattress	1
Vehicle seat you can recline (vans and SUVs)	1
Bed found in the world	1.5

A friendly survivor keeping watch within 25 m adds 1 to the score. Safety and a watch together add at most 1.5.

Water sources

Every drink of untreated water has a chance of making you ill, and the chance depends on where the water came from. The last column shows which illness you are likely to catch when it does.

Boiling, a filter, purification tablets and a solar still make any fresh water safe.

Drinking straight from the bank restores 18% thirst and carries 60% of the risk of a full bottle.

Illnesses

Bad water, spoiled food, filthy hands and a dirty camp can make you ill. All times are time spent in the world, from mildest to most dangerous, and you only carry one of these at a time.

Medicine taken before the first symptoms stops the illness completely. Oral rehydration salts restore 45% thirst and cut the fluid you lose by 50% for 15 minutes.

With body dirt at 60% or more, eating with unwashed hands has a 1.2% chance per meal of giving you dysentery.

Tetanus comes from rusty wounds. An uncleaned rusty wound has a 15% chance of it, and disinfecting the wound within 30 minutes cuts that to 4%.

Tetanus starts with lockjaw 45 to 240 minutes after the wound, muscle spasms begin 60 minutes after the lockjaw, and 120 minutes after the lockjaw it turns severe and drains your health until it kills you. A tetanus shot stops it, and sedatives hold the spasms off for 10 minutes.

Dying clears any illness.

Body dirt

Your body gets dirtier with time, blood, mud and messy work. Dirt makes new wounds more likely to start dirty, makes open wounds pick up dirt faster and gives the infected more to smell.

Time alone adds 0.5% dirt per minute, which takes you from clean to filthy in about 2.5 hours.

Smearing guts on yourself adds 25% dirt, going down adds 6%, butchering adds 5% and a melee kill adds 1%.

Each scent point lets the infected smell you from farther away. Dirty clothes on a dirty body smell worse than either alone, and a washed body in clean clothes cuts your whole scent by 10%.

Washing

Washing takes dirt off your body and out of your clothes. You can wash at open water, a basin, a bath or a shower, and soap from your pockets is used when you have it.

Soap, a shower or a wash with soap leaves your hands clean for 20 minutes, which cuts the chance of catching an illness from a sick survivor by 50%.

A washed garment comes out 85% wet and loses 1% condition, or 1.5% when you scrub blood out of it. A basin needs one water for every 2 garments.

One Laundry Soap Flakes washes 12 garments, one Liquid Soap washes 4 garments, one Soap washes 3 garments.

Wet garments dry 3% per minute near a camp fire, 1.5% per minute on a laundry line (faster in sun and wind) and 0.35% per minute folded in a pack.

Clothing dirt

Every garment you wear has its own dirt, blood, wetness and condition. The table shows the dirt levels and how long plain wear takes to reach each one.

A garment picks up 0.22% dirt per minute worn, and 2 times that while you overheat. Rain and mud, wading, falls, melee kills, bleeding and butchering add more.

A garment soaked with 70% blood counts as spoiled whatever its dirt.

Garments lose 0.06% condition per minute worn. A blow from the infected tears 4% to 8% off the garment it lands on, and a bite tears off 10% to 18%.

A garment worn down to 30% condition or less can be torn off you in a fight.

How much a garment adds to your scent depends on how much of the body it covers: top 28%, pants 22%, undershirt 22%, armor 20%, shoes 12%, hat 5%, mask 5%, gloves 4%, accessory 2%.

A wet garment left folded away sours and gains 0.12% dirt per minute until it dries.

Clothing that stops bites

Thick clothing stops a share of the bites that land on you. The numbers are for a garment in perfect condition, and a worn or torn garment stops less.

Garment	Bites stopped
Bite Gauntlets	45%
Leather Jacket	35%
Lined Hoodie	30%
Shearling Coat	28%
Buckskin Jacket	25%
Coyote Fur Parka	25%
Patched Jacket	22%
Winter Parka	22%
Patchwork Duster	20%
Fur-Lined Gloves	12%
Hazmat Suit	12%
Insulated Overalls	12%
Trapper Boots	12%
Combat Boots	10%
Hand-Knitted Sweater	10%
Storm Shell	10%
Tactical Gloves	10%
Winter Boots	10%
Snow Pants	8%
Cargo Pants	6%
Wool Gloves	4%

Everyday tops stop a small share by style: tactical 12%, military 10%, wasteland 10%, street 5%, civilian 4%. Everyday pants add 4% and shoes 3%.

However much you wear, at least 40% of bites still get through.

Fear

Your survivor's state of mind is never shown as a bar, but it changes how the body behaves. Fear is the fastest part of it, and the table shows what each level does.

Going down adds 30 fear, being grabbed 14, being bitten 12, a hard crash 10, being shot at 6 and dropping under 72% blood 18.

Fear halves every 150 seconds on your own, every 90 seconds in company and every 45 seconds while you rest.

Alone on foot at night, with nobody within 30 m, fear slowly climbs to 30.

Exhaustion adds up to 0.12° of aim sway and 6 bpm on top of fear.