If you're trying to lose weight, trainers recommend workouts that combine cardio with strength training. NASM-certified personal trainer Sydney Cummings has you covered with this 30-minute cardio and abs workout. You'll perform two exercises in a three-minute circuit in a ladder style. As Cummings explains in the video, a ladder-style workout means you'll complete two reps of both exercises, then three reps, then four, then five, and so on until the three minutes for those two exercises is up. Increasing the reps as you go is sure to pump up the intensity, so challenge yourself to push through. All you'll need is a light pair of dumbbells. Cummings uses five- and eight-pound dumbbells, but feel free to adjust the weight based on your fitness level.