I did something similar a few months ago. The SHIIT workout. :) Super high intensity integral training. I did see good results and noticed quick improvement in how I felt. The problem was I was doing it on a treadmill and began to have ankle and knee pain. I think because I wasn’t warming up enough, which they strongly warned about.
I am planning to start it back this week but dial back the intensity. I was walking for a minute, sprinting for 30 seconds, walking, sprinting. For about 20 to 25 minutes. And taking longer to warm up.
They say half your workout is your nutrition, so I also did the Eat S.H.I.T.program with great results.
And on my days off, I did No S.H.I.T.
I had the same problem with my knees and ankles pounding on the treadmill, so I bought a spinner bike on amazon. Problem solved. (And you can watch TV while you workout. It’s got a cup holder, and the remote is velcroed to the handlebar.)