Given your concern regarding your heart rate, I encourage you to discuss this further with your primary care physician
. From your question, I am unable to determine if your heart rate is 100 at the very end of a two hour run or two hours after the completion of your run.
During exercise, your heart beats faster to keep up with the increased demands of your body. Specifically, it needs to beat faster in order to pump more oxygen-rich blood to your muscles, including the heart muscle itself. In general, those who have trained their heart through intense exercise, such as athletes, will have a slow heart beat at rest that can rapidly increase during exercise and then rapidly recover afterward. In general, a heart beat that is persistently elevated after exercise may indicate poor physical fitness. However, it is also possible this is due to an arrhythmia, which can also be provoked by exercise. Some examples of common arrhythmias include atrial fibrillation, atrial flutter, AV nodal reentrant tachycardia, or atrial tachycardia. I encourage you to discuss this with your primary care physician. A typical evaluation consists of a thorough history, physical exam, and EKG
. Depending on these results, you may need to undergo additional tests, and you may need referral to a cardiologist