All you’ll need for this interval workout is a pair of comfortable sneakers (check out the best running shoes here) and something to time yourself on. If you have one of the best Apple watches or best Garmin watches, you can build an interval session as a workout on the watch, so it’ll buzz every time you need to change pace. The workout will take 30 minutes in total, but if you don’t have that long or you’re a beginner and 30 minutes feels like too big a challenge right now, reduce the number of times you repeat the circuit. Remember when walking to think about your form — keep your core enga