Quick and Dirty Measurement: Cardio Workload

Here's a great way to determine how hard your heart and lungs are working: How deeply and rapidly are you breathing?

Using the "Talk Test", breathing that allows you to easily carry on a conversation but struggle to recite poetry or say the Pledge of Allegiance puts you at about a 5-6 level on a simple 1-10 relative scale (10 = As hard as you can go; 1 = Very easy).

If you're challenged to keep up a normal exchange, perhaps grabbing a breath every word or two, you're at a "7" or 70% of your capacity. When you're really fighting to spit out a syllable or two with each breath, it's 8-9 level.

Remember that there's an inverse relationship between how long you exercise and how intensely you can work out. At a "7" you may be able to go, depending on how accustomed you are to exercise, 45-60 minutes. An 8-9 level should wipe you out in 20-30 minutes, tops.

Use this scale (Rating of Perceived Exertion, or RPE) to guide you in your cardio workouts, and remember, if you want to burn calories and improve your endurance, it's the breathing that counts.