Earlier quoted context omitted.
> Weight lifting is not aerobic, it is anaerobic. Heavy low repetition lifting is anaerobic, but around 15-20+ repetitions with lighter weights it becomes aerobic.
Super sets of 80+ reps is definitely cardio, especially on legs day.
If it's beyond 70% max heart rate, you are likely going anaerobic, muscles and heart start switch from fat to glycogen to ATP as the demand increases.
It's like a runner doing "speed work" on a track. First 800 relatively "easy". By the eight repeat, not so much.