Get a sleep apnoea disorder, lacking oxygen after partaking heartily (4,1,3)

I believe the answer is:

take a nap

'get a sleep' is the definition.
(a nap is a short sleep)

I can't explain the rest of the clue.

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.