High-intensity interval training, aka HIIT, is one of the best ways to maximize your workout time. Burn a ton of calories and boost your metabolism in little time with celeb trainer Astrid McGuire's full-body HIIT workout. It may be only 10 minutes long, but it will leave you dripping with sweat. There's no equipment needed for the workout, so press play and get at it! And if you're looking for a longer workout, double your fun time with Astrid's 20-Minute HIIT workout!