As a Hollywood actress and mom of three, Witherspoon doesn’t always have time for lengthy workouts. Which is why she’s a fan of super-challenging—yet short—HIIT (high-intensity interval training) workouts. In fact, her go-to cardio routine takes just 10-minutes to complete. Yes, seriously! Fitness experts swear by high-intensity bursts, which burn calories, curb appetite, and promote weight loss. Plus, the short length allows busy bees to easily pencil it into their schedules. That means you can totally squeeze in Witherspoon’s routine between driving the kids to soccer practice and catching up on work emails.
So what does her exact routine entail? Reese starts off by jogging at a steady 6 mph pace for a minute. Then she ups the incline to 1 percent and jogs for 45 seconds at 7 mph. After that, she increases the incline to 2 percent and runs at 8 mph for 30 seconds. She then recovers by walking at 0 percent incline for 60 seconds. Reese repeats this speed pattern three times, slowly but surely increasing the incline to challenge her body. So, the second round starts at a 1 percent incline, progresses to a 2 percent incline, and then ends with a 3 percent incline and a short, one-minute recovery. And the third and final round begins with a 2 percent incline, ups to a 3 percent incline, and finishes off with a 4 percent incline. She cools down with a one-minute walk at zero percent incline.
Incorporating a HIIT routine like this one into your fitness regimen has countless benefits besides speeding up your metabolism and burning fat. In one study published in the journal BMC Endocrine Disorders, overweight participants who performed just 12 short 15-minute HIIT workouts improved their insulin sensitivity by an impressive 23 percent! So next time you’re at the gym, try this muscle-toning cardio workout and dedicate a different day for weight training to build lean sexy muscle. For even more ways to get into shape—fast, check out this Celebrity Trainer’s Essential Trick For Rapid Weight Loss.