Spinning: How Hard is Hard Enough?

I'm already training for next year's LifeCycle, and have been taking a lot of spinning classes. The instructor recommended that I buy a heart rate monitor so I can my heart rate was during the classes. How do you figure your maximum heart rate? Should I really push myself hard in these classes to get my heart rate up?

Yes—to get the full benefit of cardiovascular exercise, you do have to get your heart rate up. Since you're training for a long cycling event, your goal is to increase your endurance, so it's important for you to "push yourself" and get your heart rate up. But remember, always listen to your body—you and you alone are the best person to determine your level of effort.

To figure your maximum heart rate, you start with the number 220 and subtract your age. You want to exercise at about 65% capacity of that number, so multiply that number by .65 and you'll have your "target" exercise range. Remember, this is just an approximation, so if you don't feel that you're getting enough from that level intensity, you may want to bump it up to 75-80% of your maximum heart rate. Conversely, if you feel too winded at 65%, you can always slow down a little.