VO2 max is a score that measures your aerobic fitness. The more fit you are the higher the score. Measuring VO2 max is a good way to determine the benefits of cycling.The typical way to measure VO2 max is to running on a treadmill to the point of exhaustion in a lab. Recently researchers have develop a calculator that  is very accurate measurement sans the running. You will also learn your fitness age.

You need to know your approximate resting heart rate (this can done by lying down for a few minutes with your heart monitor on), your waist circumference and answers a few other questions. Go to:

worldfitnesslevel.org

 If you take the "test". post your scores versus your chronological.