Week 4 is the HARDEST week, by far. For me, even the 20 minute run wasn’t as hard to get tghourh as those first 6 minute runs. It gets better every time tghourh, but I totally feel your pain. I also have thought many times that this app is perfect except it could use a few more weeks in the program between weeks 3 and 4, and probably also to work up a little more gradually to that first 20-minute run. Here’s what I did to remedy the issue in lieu of the extra built-in weeks: I used to use the Nike Pro Training Boom app (which allows you to program in your own intervals) to program in an altered version of Week 3 where I run 3 minutes and four minutes instead of 3 minutes and 1.5 minutes. I felt like that was in-between enough to bridge me over and help me get used to those 4 and 6 minute runs in week 4. If you use the GPS feature, Runkeeper is a free app that has a GPS feature that you could run in the background with the NPT app for that time period.The other thing I do doesn’t involve extra apps at all. On any given day if I TRULY can’t do an interval, I just take a few seconds (up to a block) to walk a little until I feel like I can run again. It is still pretty close to the intensity of the intended workout, but it really boosts my morale!