Dialogue:

Anna: Hey, Tom! You look tired. What happened?
Tom: I stayed up all night finishing my project.
Anna: Oh no! You should take a short nap to catch up on your sleep.
Tom: I know, but I have another meeting in an hour. Maybe I'll just grab a coffee instead.
Anna: Don't burn yourself out! You need some rest.

In the dialogue above, the expression "catch up on" means to: