I am on second week of c25k but started using someone else's formula before finding the NHS version. This week is 2min run, 2 min walk x 7 and the step up from a minute to 2 minutes is killing me and a little of my motivation. I am about 3 stone overweight and my whole body is feeling the strain of running with that kind of baggage on board. I am doing this with my partner and she doesn't want to go down to 90 seconds but I would prefer to do this without the shock to the system. As far as I am concerned if I am out 3 times a week running some and walking some this is a great improvement. Next week is supposed to be 3 min run, 2 min walk x 7m, 3 days a week and I feel that the NHS version is more gentle. Anyone else switch versions or find the increases too much?