Rest up phrasal verb informal
Peter really needs to rest up for a few days before getting back to work.
He looks so tired. He needs to rest up.
To not wonder, worry or be surprised about what is not predicted will happen in life because anything could happen
Go to bed
To take a seat and relax
Sleep continually for a long period of time
To keep calm, or try not to lose composure, temper, or nerve
The verb "rest" should be conjugated according to its tense.
This phrase is believed to derive from the 19th century in the USA.