Hello, I Have A Resting Heart Rate Of 54beats Per

Hello, I have a resting heart rate of 54beats per minute, I am 105 kilograms and 180cm tall. I like to walk, but would not say I am fit, i can walk 5 miles with realative ease, I have just come back from 30 days in the south west states visiting and camping in most of the national and state parks, without any discomfort or breathlessness, but my doctor is concerned my pulse rate is too low, should i be concerned?