Generally, so long as you feel fine and your heart rate increases normally with increased exertion, you should be proud of you low resting heart rate. It is most likely a result of your better cardiovascular condition. However, if you have any concerns, go see you doctor. He'll probably congratulate you and tell you that your wasting his time. But that's the best thing a doctor can tell you!

My resting heart rate is in the same range. So is George Dubya's so you are in good company.