I graduated several months ago, and try to do my 30 minutes three times a week (still only doing 3.5km in my 30 minutes, but gradually working towards getting faster.) I'm going on holiday next week and will be in a hilly part of the country (where I am is dead flat, the only slopes I deal with are bridges). Anyway, I figure I might need to go back to run/walk intervals. What do folk think ? I was wondering about 5 run, 1 walk, or something... Any experience out there ?