Causes

Often the cause of your heart palpitations can't be found. Common causes include:

• Strong emotional responses, such as stress, anxiety or panic attacks
• Depression
• Strenuous exercise
• Stimulants, including caffeine, nicotine, cocaine, amphetamines, and cold and cough medications that contain pseudoephedrine
• Fever
• Hormone changes associated with menstruation, pregnancy or menopause
• Too much or to little thyroid hormone

Occasionally heart palpitations can be a sign of a serious problem, such as an overactive thyroid gland (hyperthyroidism) or an abnormal heart rhythm (arrhythmia).

Heart rhythm changes (arrhythmias) might cause a very fast heart rate (tachycardia), an unusually slow heart rate (bradycardia), a normal heart rate that varies from the usual heart rhythm or combination of the three.