HIIT—or High Intensity Interval Training, for the uninitiated—is one of the trendiest exercise programs out there at the moment, but getting started as a first-timer can be daunting, to say the least.

If you’ve never tried high-intensity interval training (HIIT) workouts, it’s worth serious consideration. Why? In short, HIIT, which involves bursts of high-intensity cardio and strength exercises ...