Fast Heart Rate Causes

A fast heart rate is referred to medically as tachycardia. A heart rate that is more than 100 beats per minute is considered to be rapid. Though it is often harmless, a fast rate can indicate a serious condition. When the heart beats fast for a long period of time, the tissues of the body may not get adequate oxygen and nutrients. Treatment for tachycardia is dependent on its cause. Many cases are temporary and require no treatment.


Exercise temporarily raises the heart rate. Ten minutes of jogging for a person unaccustomed to exercise may lead to a heart rate of 120 beats per minute or more. This elevation is normal and expected. Someone in top physical form will also experience a rise in heart rate due to sustained physical activity though his heart rate usually remains well below 100. Someone in poor physical condition, however, may experience tachycardia from a 100-foot trek up a hill.

Emotional Distress

Extreme emotional stress can raise the heart rate. Common triggers include fear and anxiety. People suffering from a phobia, generalized anxiety disorder or panic disorder may have significant heart rate elevations when distressed. Pain also causes tachycardia in many people.


Many varieties of drugs are responsible for heart rate elevation. Common culprits include caffeine, nicotine and alcohol. Prescription medications such as thyroid medicines, atropine, catecholamines and aminophylline are known to increase heart rate. Mayo Clinic explains that some illicit drugs such as cocaine can also cause temporary tachycardia.

Chronic Heart Conditions

A variety of chronic heart problems may be responsible for episodic or continuous tachycardia. Damaged heart tissue, problems with the heart’s electrical system, heart valvular disease, cardiomyopathy, coronary artery disease and heart problems existing from birth are possible causes of fast heart rate.

Other Medical Conditions

The manual “Medical-Surgical Nursing” indicates that hyperthyroidism can cause an elevated heart rate. Other medical conditions known to be responsible include lung diseases, pulmonary embolism, low blood oxygen, high blood pressure, electrolyte imbalances and anemia. When the body undergoes a life-threatening event such as heart attack, heart failure, shock or hemorrhage, the blood pressure and heart output may fall. The body often raises the heart rate in response to these events. Finally, acute conditions such as fever and infection can lead to a fast heart rate.

About this Author

Lucy Boyd is a registered nurse who graduated summa cum laude from the University of the State of New York – Regents College with a Bachelor of Science in Nursing degree in 2000. A professional writer since 2007, Boyd is the author of two medical books. Trade magazines such as “PI Magazine” call on her to create feature articles explaining psychiatric and medical issues.