A normal heart rate for a healthy adult is between about 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. This includes some asthma medicines.
Smoking, alcohol, caffeine, or other stimulants, such as diet pills.
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 for an adult.
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, chest pain or pressure, shortness of breath, dizziness, lightheadedness, or fainting.
Author: Healthwise Staff Clinical Review Board: All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.