I have just begun riding a stationary bike...been doing 30 minute sessions 3 times a week on my non-lifting days. Anyway while on the bike today, every 5 minutes i would crank up the intensity and resistance and pedal full speed for 45 seconds, then return back to my normal pace. I did this 4 times within the 30 minute work-out. Is this a form of HIIT? Also, im starving after i do cardio just like when i lift. Are protein shakes good for post cardio work as well?

Thanks in advance.

I was completely exhausted after my work-out. I had planned on increasing the "all out" time but like i said, im just beginning and trying to ease into it. I just got to where im doing a whole 30 minute work out much less full on HIIT. What i'll be doing is increasing my "all out" time from the point of odd interval training until it progresses to HIIT.