My heart rate has been around 43 resting. i had anorexia last year and still struggle. but when does this rate become dangerous?

Bradycardia: Many conditions can cause a slow heart rate "bradycardia". It is commonly found in well conditioned athletes. It becomes a problem if it causes symptoms such as dizziness and fainting spells "syncope". See your doctor to do a holter monitor and echocardiogram. The holter checks the heart rhythm over a 24 hour period. ًThe echo checks in the structure of the heart and the function of the heart.