I used to do hiit in the morning a while back and got good results. I have been doing 45 minutes on empty at 125-140 BPM and sometimes it feels like I am hardly doing anything. One morning I kicked it up to 150-160 BPM and that felt good. My max HR is 189. Did the Hiit in the morning get my bopdy all whacked up and now the slow cardio just will not cut it.
