We were all out of breath when we got to the summit.
Prince Andrew, out of breath with his rapid ride, spoke quickly.
My doctor says I'm always tired and out of breath because I'm anemic.
When stipulating aerobic exercise this means that the activity needs to make the individual moderately out of breath for a sustained period of time.
This includes things like feeling out of breath even with minor exertion, or not fitting in a standard booth at the restaurant.