Walking fast is too easy for you so you need a 40% incline? Sounds awful hard on your aging Achilles tendon.
Try this walking routine and tell me how easy it is. Most treadmills in the US show an electronic track showing 440 yards or a quarter mile. Some US treadmills instead of a track will show .25 as being a quarter mile. Start walking at zero grade or level ground at 3.8 MPH. This is a brisk walk. After completing one lap. Raise the incline 1%. Complete that second lap and then raise it to 2%. Keep that sequence up with each lap increasing 1%. If you go from level to 14% grade one lap at a time with 1% increase you will be in good cardio shape. Good enough to start a running program.
One of the reason steroid users hate fitness is because without the drug assist they are stuck with real reality of their limitations. It's easy to syringe and make drastic gains in 6 weeks. What's hard is doing an athletic work routine.
Great suggestion and thanks for the input.
BUT, your cardio routine is very similar to what I'm currently doing now.
I NEED some form of competitive end game to feel motivated.
I need to bite the bullet, diet hard and for better or worse, do the masters nationals this July.
I've always wanted to do that BUT ended up talking myself out of it for many years .
It may not be sensible, but it's where my real passion lies.