rest and sleep

adventurers, as well as other creatures, can take short rests in the midst of a day and a long rest to end it.

short rest

a short rest is a period of downtime, at least 1 hour long, during which a character does nothing more strenuous than eating, drinking, reading, standing watch, or tending to wounds, at the end of a short rest, the creature regains one quarter of its hit dice, for example, if a character has eight hit dice, it can regain two spent hit dice upon finishing a short rest, a character also recovers one level of exhaustion when it finishes a short rest, a character on half rations can perform one short rest a day, two if on full rations, and three if on extra rations

Long Rest

a long rest is a period of extended downtime, at least 8 hours long, during which the creature sleeps for at least 6 hours and performs no more than 2 hours of light activity, during which a character does nothing more strenuous than eating, drinking, reading, standing watch, or tending to wounds, if the rest is interrupted by a period of strenuous activity — running, fighting, casting spells, or similar adventuring activity — the characters must extend the rest by one hour per interruption to gain any benefit from it

at the end of a long rest, the character regains one half of its hit dice, for example, if a creature has eight hit dice, it can regain four spent hit dice upon finishing a long rest, a character also recovers two levels of exhaustion when it finishes a long rest, a character can't benefit from more than one long rest in a 24-hour period or within 12 hours of the previous long rest

sleep

while a creature sleeps, it is subjected to the unconscious condition, here are a few rules that expand on that basic fact

waking someone

a creature that is naturally sleeping, as opposed to being in a magically or chemically induced sleep, wakes up if it takes any damage or if someone else uses an interact with object to shake or slap the creature awake, a sudden loud noise — such as yelling, thunder, or a ringing bell — also awakens someone that is sleeping naturally

whispers don’t disturb sleep, unless a sleeper’s passive wisdom (perception) score is 15 or higher and the whispers are within 10 feet of the sleeper, speech within 10 feet at a normal volume awakens a sleeper if the environment is otherwise silent (no wind, birdsong, crickets, street sounds, or the like) and the sleeper has a passive wisdom (perception) score of 10 or higher

movement within 10 feet of a natural sleeper will wake it if the moving creature fails to beat the sleeper’s passive wisdom (perception) with a dexterity (stealth) check, this check does not the violate lawful alignment unless the lawful character is hostile to the sleeper

sleeping in armor

sleeping in light armor has no adverse effect on the wearer, but sleeping in medium or heavy armor makes it difficult to recover fully during a long rest.

when you finish a long rest during which you slept in medium or heavy armor, you regain only one quarter of your hit dice, if you have any levels of exhaustion, the long rest reduces your exhaustion level by one, creatures with the medium armor master feat don’t suffer from this effect

going without a long rest

a long rest is never mandatory, but going without one does have its consequences, whenever you end a 24-hour period without finishing a long rest, you must succeed on a DC 10 Constitution saving throw or suffer one level of exhaustion

it becomes harder to fight off exhaustion if you stay awake for multiple days, after the first 24 hours, the dc increases by 5 for each consecutive 24-hour period without a long rest, the DC resets to 10 when you finish a long rest