Cardio training is an important part of the Back to Fit trainer. Your heart is a muscle, and all muscles need to be trained. Cardio is also a great way to burn excess body fat and improve your body composition.
For today's session, you'll grab a bike, treadmill, stair machine, or elliptical machine, and go to work. Choose your equipment based on how your body feels. If you have knee injuries, then do the work on a bike. If you like running, then go for the treadmill. The equipment you use isn't important, but your intensity level is.
The work you do should be out of an intensity level of 10. So, if a 10 is the hardest you can possibly work, then the walking portion should be at a 3, the jogging portion should be at a 6, and the running portion should be at an 8.
Just like the resistance-training workouts, you'll do a circuit for 25 minutes. Keep moving through the entire thing!