Immediately following I wasn't sure and wanted to give an honest answer.
Yes. Yes. Yes.
What I did to prove this to myself:
I repeated a cardio routine (P90X Kenpo)that I thought was pretty tough as a P90X grad. (Of course, P90x focuses on resistance and less focus on cardio.) I kept a journal at that time and my heart rate would be high to very high during this routine. Despite doing the routine as hard as I could as it was laid out, I could not get over the moderate heart rate range for me. I actually thought about doing ski abs, pushup jacks, and diamond jumps to add some intensity and INSANITY to this workout.
So YES you can believe when you are finished with Insanity you will be in the best shape of your life and that every dollar spent on this program and every drop of sweat was well worth it! For me, I believe that the HIIT or max intervals (or whatever you want to call it) has been the missing link in my overall fitness. I have never worked out at this intensity level in the past.
Good luck with your workouts sunnyday!!
