HIIT training is awsome, but work your way up to it. Running half a mile and gassing is horrible man. I feel sorry for you
I usually run about 2-4 miles every 2nd day. After a work out at the gym i run 2 miles. When I do my HIIT training i usually run about one mile, then when i get a good heartrate going i do side to sides, cross overs and sometimes even lunges. ANd offcourse sprint every every third lap. Im such a lazy runner tho...i hate running.