The information below are my training paces which I determined using a recent marathon race time (4 hours) and the McMillan Running Calculator (MRC). I have modified some of the numbers from the running calculator to include the faster ranges specified by the FIRST Marathon Training Program (from the book Run Less, Run Faster ).

The heart rate information was calculated using my maximum and resting heart rate. Some runners do pace based training, others do heart rate based training, and still others use a combination of the two. My training is mainly pace based, although I analyze the heart rate information to determine fitness trends. Because it is so subjective, perceived exertion level is not always an accurate reflection of current fitness. Heart rate measurements provide me with a more accurate assessment. The heart rate information allows me to answer questions such as "Is completing X distance at Y pace becoming easier?". With proper training, over time the average heart rate for a given pace and distance generally decreases, indicating that the heart is having to work less to maintain that pace for that distance. However, heart rate can be affected by factors such as temperature and illness. In addition, if the heart rate monitor does not have good consistent contact with the skin, it can have erroneous readings.