Sunday - Improvement?

This was really quite good - I ran 3 mins/walked 3 mins and my heart rate didn't hit zone 5 until the 3rd interval and even dipped into zone 2 in the second walking interval - could this be improvement at last?!

Edit: Ok, I don't understand running. I did virtually exactly the same thing today as I did yesterday yet today there is huge improvment. I don't get it... bring on more days like today though.