The heart pounding easily is often a sign of a very unconditioned or sedentary body and because of this, you must slowly build your exercise program up to the point where you no longer are huffing and puffing. This may take a long time or it may mean that you have a problem with your heart, and should see a cardiologist to find out what is wrong. Often times, people who are 70 to 100 lbs or more overweight will huff and puff, and have a hard time with their heart rate and just losing the weight will fix it. But to be safe, see your family physician or a cardiologist to check out any heart-related problems.