Thursday: Cardio Now that your body is getting accustomed to cardio, it's time to up the intensity with a 26-minute rolling hills treadmill circuit that mixes incline with speed. 5 minutes: 3.3 speed at 5 percent incline 2 minutes: 3.6 speed at 7 percent incline 1.5 minutes: 4.5 speed at 5 percent incline 1 minute: 3.6 speed at 5 percent incline 2 minutes: 4.5 speed at 5 percent incline 1 minute: 5.5 speed at 7 percent incline 1 minute: 4.5 speed with no incline 2 minutes: 4.7 speed with no incline 1.5 minutes: 5.6 speed with no incline 1 minute: 5.0 speed at 5 percent incline 2 minutes: 4.7 speed 5 percent incline 1 minute: 4.0 speed 5 percent incline 5 minutes: 3.0 speed with no incline Image Source: Getty / skynesher