Heart palpitations are best described as the sensation of the heart beating irregularly. Under normal circumstances, an individual is not consciously aware of his or her heart beating. When experiencing a palpitation, the heart seems to be beating loudly and forcefully, sometimes seeming even to stop momentarily. Many things can cause heart palpitations. In the vast majority of cases, the cause is either related to your heart or is unknown. Non-heart-related causes of palpitations include:
--Strong emotional responses, such as stress or anxiety
--Strenuous exercise
--Caffeine
--Nicotine
--Fever
--Hormone changes associated with menstruation, pregnancy or menopause
--Taking cold and cough medications that contain pseudoephedrine, a stimulant
--Taking some asthma inhaler medications that contain stimulants