Ive been doing HIIT where I sprint as fast as possible for 30 sec and then rest for 30 sec. I do this 10-15 times. Another one i do is sprint for 1 min followed by 2 min rest and do this for 30 min. my problem is that although i do get tired and look forward to the end, after i finish my cool down i feel like i could go again and i could do it more than 3 times a week. i dont know how to do HIIT so i can drop body fat.