Exercises to improve oxygen levels (8)

I believe the answer is:

aerobics

(Other definitions for aerobics that I've seen before include "Exercise that increases the need for oxygen" , "System of exercises" , "Exercises designed to strengthen heart and lungs" , "Physical exercises" , "Fitness system" .)

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.