Human has provided you with an excellent answer and from my perspective, if you are symptomatic, then you should get your low heart rate looked into.
When I say symptomatic, I mean lightheadedness, feinting episodes, chest pain, breathlessness etc. It suggests that perhaps your cardiac output is not sufficient to meet the your physiological demands and hence your symptoms.
In addition to the causes Human have mentioned, slow heart rate can be due to an increase in vagal tone (the nerve that slows down the heart rate), a lack of sympathetic response (the system that increases the heart rate) or an intrinsic issue with the heart muscle.
Seeing a physician or a GP in the first instance is a good step. They can assess you clinically and perform some baseline investigations before referring onwards if necessary.
I hope this helps.
BW
Dr Dinesh
