I managed week three even though I worried about it, but feel really tired the following day. It would not occur to me to think about running on the rest day, but I have bounced back the next day ready to run. I don't feel badly out of breath at the time but my legs feel really tired.
I think I could manage one lot of 5 minutes but two lots and only a 90 second recovery after the 3 minutes seems a lot. This seems such a jump from week three. Ahhh