I am a 12-year-old runner who can run a 7:10 mile. I was wondering how long and how fast would I need to walk on the days I don’t run to get benefits. (Normally, I run for about 15 minutes.) Currently, I’m training for a 1.5-mile race, but my doctor won’t let me run every day because of my ankles and my age.
Because I’m not sure exactly what your needs are, I’ll answer your question for two different scenarios.
If you intend your walking day to be a rest day, then just walking at a comfortably brisk pace is what you need. However, if you want it to be a training day, then you may need to learn some racewalking techniques in order to go fast enough to get your heart rate elevated.
Mile for mile, walking burns as many calories as running; it just takes longer to do it. But to get equal cardiovascular benefits – that is, to get your heart rate into your target range – you may need to upgrade your walk.