I have edge 800 (bike gps) and heart rate strap. Resting is 58 and max heart rate reserve is 157.
Now what am I looking for while riding? How do I know if I'm over exerting my heart. Thanks for help
You can find a lot of information out on the web if you Google something like "heart rate training zones". There are a lot of charts, a lot of methods, and a lot of opinions to weed through before you decide what it best for your individual fitness level and goals.
The simple answer to your question on over-exertion would be "don't exceed your max heart rate." Then the next question is "How did you determine your max heart rate? From a standard chart or formula?" Charts and formulas give an approximation for the person of average health and fitness level. If in doubt, check with your physician.
Once you know your personal max heart rate, you'll want to set up your heart rate zones so that you can use your monitor effectively while you are riding.
Below is a link to an article that I just pulled up. You might read here about the 5 training zones to help you understand how to set up your heart rate zones on your Garmin, and then decide which zones you should try to stay in while you are riding. It's a very individual thing, so you need to have a basic understanding of the concepts and then tailor it to your own needs.
