If a persons's heart rate is lower than 60 beats a minute due to a fault in the heart’s natural pacemaker, the risks include dizziness, fatigue, chest pains, shortness of breath, fainting, seizures or death, reports WebMD. When there are no other underlying conditions, having a low heart rate, also known as bradycardia, can simply be a sign that the person is very fit.
Medical causes of bradycardia include aging, heart disease, heart attack, endocarditis and myocarditis infection and hypothyroidism. An electrolyte imbalance, a high blood potassium level and medication to treat high blood pressure can also significantly lower heart rates, explains WebMD.
Doctors usually treat a heart that beats too slowly due to a damaged electrical system with a pacemaker, an under-skin device that enables the heart to pump blood at a normal rate. People over 65 are the most likely group to need a pacemaker, according to WebMD.