Can low Testosterne cause low heartrate. I have had all kinds of test all doctors say my heart is fine but my heart rate cause into the upper 40 s and stays around 60ish most of the time. Standing it ll get up to 70 s it s rare it gets into the 80 and 90 s. I m 29 and overweight not much. I don t really exercise, even though i need too. I take .125 mg of klonapian at bed time. It never gets low when at the doctors are during test. White coat syndrome I guess. So it is really scary.