If you can do 25-30 minutes of KB swings, you must be a machine! The best I ever got was 10 minutes of swings, 20 swings per minute, with a 50 lb KB. How heavy is your KB?
Anyway, your cardiovascular fitness should be excellent if you can do that. Also, you might be getting in too much cardio if you're going that every day. If you start dragging and feeling sluggish, then you're doing too much and need to back off. IMO, you'll probably be okay doing it every day for a few weeks before you start to notice performance issues.
Poke it quickly, with a stick.