I am still walking 5 km in 50 minutes, same as last year. We had a viciously bad winter so I'm not walking up to my best yet. I have noticed that in ketosis I breath much easier, and have been introducing intervals of jogging during my walk. Of course that brings my 5 km time down to 40-45 minutes. So I would have to say my 5 km time has actually decreased since being in ketosis.