Big Lungs On The 3-2-1

I went out for a run yesterday planning to do a road interval workout. It was either 2 minutes hard effort with 2 minutes recovery jog or the 3-2-1 intervals ( One set consists of: 3 minutes hard effort, 1 minute recovery jog, 2 minutes hard effort, 1 minute recovery jog, 1 minute hard effort, 2 minutes recovery jog, for a total of 10 minutes each set). During the first 10 minutes of warm-up, my legs were feeling pretty good so I opted for the harder 3-2-1 intervals, maybe at least 3 sets of it. As far as my breathing was concerned, the first set felt good, the second felt better, by the third set I was feeling really, really good. It felt like I had really big lungs where despite having to breathe harder due to the increased effort my lungs felt bottomless. So I kept that feeling going until I finished an hour: 10 minutes of warm-up plus 5 sets of hard intervals. The speed of my run may have looked very slow to any casual onlooker, but the intensity and effort I put into it made it a very good workout for myself. The only reason holding me back from being able to run any harder is the pain in my ankles. Yesterday, my ankles cooperated.