In a perfect world, we'd all have a good hour of free time every day, specifically for working out. Unfortunately, that's not the case—and some days, between making time for work, friends, and family, it's hard enough to just find time to take a breath, let alone crush a workout. That is, until high-intensity interval training (HIIT) gained popularity. For the uninitiated, HIIT workouts are a quick, efficient way to sneak in exercise, but the benefits go way beyond simply fitting it into your schedule. “HIIT training can improve anaerobic capacity, cardiovascular health, and result in fat loss,” says Lacee Lazoff, NASM-certified personal trainer based in New York City and creator of Bells Up . “It’s effective when work’s performed in short intervals at maximum capacity, followed immediately by modesty intervals of very low capacity or rest.” RELATED: 7 HIIT Mistakes You’re Probably Making So what does an effective HIIT workout look like? Lazoff suggests that...