Another pinner said: This website is AMAZING. It is my workout bible, and best of all, its completely FREE. Tons of workout vids and plenty more to stave off ruts. Most of the routines are between 12-20 mins long and that's all you need.
Cardio Workout: Beginner Treadmill routine 40 mins -I am new to exercising so I had to adjust down a little. I would suggest for real beginners to adjust down one full speed on all of the intervals to start with than work up to this chart