Topic Overview

A normal heart rate for a healthy adult is between 60 and 100 beats per minute. Heart rates of more than 100 beats per minute (tachycardia) can be caused by:

• Exercise or stress. This fast heart rate usually returns to normal range (60 to 100 beats per minute) with rest and relaxation.
• Illnesses that cause fever. When the cause of the fever goes away, the heart rate usually returns to normal.
• Dehydration. When the dehydration is treated, the heart rate usually returns to normal.
• Medicine side effects, especially asthma medicines.
• Heavy smoking, alcohol, or too much caffeine or other stimulants, such as diet pills. Stopping the use of tobacco, alcohol, caffeine, or other stimulants may help your heart rate return to normal.
• Cocaine, amphetamines, and methamphetamines.

Babies and children younger than 2 years old have higher heart rates because their body metabolism is faster. Heart rates decrease as children grow, and usually by the teen years the heart rate is in the same range as an adult’s.

A fast heart rate may be caused by a more serious health problem. A heart problem or other medical conditions may sometimes cause a fast heart rate. A fast heart rate may cause palpitations, dizziness, lightheadedness, or fainting.

Heart rhythm problems that cause a fast heart rate include atrial fibrillation and supraventricular tachycardia (SVT).

If you have heart disease or heart failure, or if you have had a heart attack, be sure you understand the seriousness of a change in your heart rate or rhythm.