Questions / Advice regarding Protein Supps

Got a question regarding High Intensity Training (HIT) and treadmills...


For the last 2 days I have done 2 miles on the treadmill in what I believe to be a HIT regimen, I go at speed 4 for 90 seconds then speed 6.7 for 45 seconds and repeat till I hit my 2 miles...

This definitely elevates my heart rate, which is the theory between HIT as I understand it, my question is am I going fast enough / differing my rest and speed sets enough to get the benefits that HIT claims? or would my time be better spent running a steady pace?