So I tried my own modified version of HIIT today, and I have to say I actually enjoyed it! It went by a lot faster than just my traditional 30 minutes of jogging on the treadmill. I know this isn't super high speed, but it worked for me for now:
I started out with a 4 minute warm up at 4.3 and then boosted it up to 6.0 for 60 seconds. Then I went back down to 4.3 for 3-4 minutes depending on how my body felt, and then boosted it up to 6.0-6.3 for 60 seconds. I did this for 20 minutes and then went back down to 3.8 for the last 4 minutes. I
I feel very energized and might try this again on Monday. I'm surprised it did go by as quickly as it did. Probably because I was listening to my body more and watching the time for interval changes instead of just focusing mindlessly on the TV.