25 minutes! I might have gotten a bit carried away and decided to nearly sprint the last minute but I was just really happy I had the energy to speed up in the last five minutes. I can't believe I'm able to keep going for so long now. I wasn't utterly utterly unfit at the beginning (regularly walked for a number of miles) but I never did any strenuous exercise. So for people who are looking around on the forum and thinking they can't do it, you can! If you're starting off with less fitness than me I recommend some walking for a while before you start the programme but ,otherwise, go for it! It's amazing how your body gets better at it.