When your pulse is low, it means your heart rate is low, and that means your heart is having to work harder to pump your blood. Low pulse rate can be caused by a disruption of the electrical impulses that keep your heart in rhythm.
Have you had an exam by your PCP and has he mentioned hypothyroidism ? Low pulse rate is among the many symptoms of hypothyroidism.
You will see articles that will explain young altheletes may have a low heart rate which is normal for them but these are the road warriors that take exercise seriously - the runners, the bikers, the triathalon people.
My best advice - do check in with your Dr. and I am glad to meet you here in the heart forum.