As fitness improves and your heart and circulation becomes more efficient (pumps out more blood for each beat) you should see a reduction in heart rate for a particular load or speed. Graph the heart rates over training periods or seasons.
Resting heart rate should also show a reduction as fitness improves. Some very talented and fit endurance athletes (world class) would have resting heart rates in the low thirties and quite a number of endurance athletes would record resting heart rates in the forties.
Some of the best road cyclists have been reported as having rest heart rates as low as 28 beats per minute.
If you keep a training diary and record resting and exercise heart rates you will see the changes as your fitness improves or disimproves.
There are some excellent Heart rate monitor options on the market that allow you to download a lot of useful data to computor files.
