Fatigue, Exhaustion and Rest

Fatigue

1st Step: After staying up all night, you will start the next day with a level of exhaustion. Even if taking a short rest, you will begin the day with the Fatigued status, which grants disadvantage on initiative but does not count as a level of exhaustion.
2nd Step: After staying up all of the next day after not resting the night prior, you will start the night with an additional two levels of exhaustion. Advancement in exhaustion will continue in this manner, night into day and vice versa until a long rest is taken.

Rest

Long Rest: All normal rules apply to a long rest, except that a long rest in a bed can cure one level of exhaustion, and a long rest while bandaged will heal all Lesser Injuries.
Short Rest: All normal rules apply to a short rest, except a short rest cannot cure fatigue, and when taking a short rest instead of a long rest for sleeping and recovery you gain one less level of exhaustion from fatigue than you normally would. Additional short rests cannot be taken to avoid further fatigue for each day/night period.

Exhaustion

Level	Effect
1	You gain disadvantage on Ability Checks.
2	Your speed is halved.
3	You gain disadvantage on Attack Rolls and Saving Throws.
4	Your hit point maximum is halved.
5	Your speed is reduced to 5 feet.
6	You die.