Caffeine, nicotine, diet pills, cocaine or anxiety may cause a rapid heartbeat, according to MedlinePlus. Other causes include fever, exercise or disease. Prevention may include lifestyle changes, including a better diet and exercise.
Doctors call a heartbeat of more than 100 beats per minute tachycardia, explains the American Heart Association. The rapid heartbeat may begin in the upper chambers of the heart, the lower chambers or the heart's natural pacemaker, the sinoatrial node. Tachycardia that begins in the upper chambers of the heart usually does not require medical treatment. However, if the rapid heartbeat occurs regularly or for an extended period, the doctor might suggest treatment or lifestyle changes, such as eliminating coffee, tobacco and alcohol use or getting more rest.
Sinus tachycardia is generally a fast but steady heartbeat brought on by emotional stress, fever, drug use or strenuous exercise, states the American Heart Association. With this type of rapid heartbeat, doctors generally treat the underlying cause. The body may tolerate a rapid heartbeat beginning in the lower chambers of the heart, but the condition can be life-threatening. This type of rapid heartbeat may be due to a lack of blood flow from the coronary artery and can lead to coronary arrest.