What is Considered A Dangerously High Heart Rate?

A normal heart rate in a healthy adult range from 60 to 80 beats per minute at rest, Infants and children has higher heart rates than adults in the normal state. The heart rate can rise during exercise, running, high fever, flu, excitement, consumption of nicotine or caffeine, surgical operations, and treatment procedures. When heart rate in adults exceeds 100 beats per minute at rest, then the condition is called tachycardia which has a pathological reason behind. It becomes extremely dangerous for the patient as it may cause heart failure, cardiac arrest, and even death.

What is Considered a Dangerously High Heart Rate?

In healthy adults, a normal heart beats at the rate of 60 to 80 beats per minute at rest. Heartbeats are regulated by electrical impulses originating from the natural pacemaker in the heart named as SA node located in the right upper chamber of the heart. Any condition or disease may interrupt this electric supply in the heart leading to increase in the heart rate. The increase in heart rate in adults depends on the age and physical condition of the affected person. The heart rate above 100 beats per minute is considered as high heart rate and is termed as tachycardia.

There can be physiological and pathological reasons for the increase in heart rates. The physiological causes of high heart rate are vigorous physical activities like exercises, pregnancy, anxiety, illness or excitement. The heart rate may go faster at the rate of about 100 to 120 beats per minute. The reasons can also be fever, dehydration, caffeine, medicines or drug abuse for such high rate heart rate. It is not considered dangerous but it should be controlled.

But when heart rate exceeds 120 beats per minute in adults at rest, then there can be a pathological cause. It should be managed properly to bring the heart rate to the normal values by management through medicines according to the underlying cause.

The resting heart rate exceeds above 140 beats per minute, then there is definitely a pathological reason behind. The heart rate above 140 beats per minute is considered dangerous value for tachycardia and it must be managed immediately in the emergency department.

The possible pathological causes behind such a fast heart rate are Heart diseases- coronary heart diseases, heart valve disease, infections and tumors in heart, heart failure, heart attack, abnormalities in the heart present since birth, lifestyle factors- consumption of alcohol, cocaine, other drugs and smoking, hypertensive disease, hyperthyroidism, reaction to certain medicines, imbalances caused by electrolyte, some lung diseases like bacterial pneumonia, pulmonary embolism, chronic obstructive pulmonary disease, anemia, hemorrhage, Wolff-Parkinson white syndrome, and Sarcoidosis.

High heart rate sometimes does not reveal any symptom. Tachycardia or high heart rate impairs the normal functioning of the heart. With such a high heart rate, the heart is unable to pump sufficient blood supply to the rest of the body resulting in symptoms like dizziness, low blood pressure, pain in the chest, difficulty in breathing, and fainting.

The complications of dangerously high heart rate are

Blood Clots- High heart rate can result in clot formation in the heart vessels leading to heart attack.

Heart Failure- Heart may work faster to meet blood supply requirements in tachycardia resulting in heart failure.

Frequent Fainting- With high heart rate, oxygen supply to brain get reduced, resulting in frequent fainting.

Sudden Death- High heart rate may cause irreversible damage to the heart that may lead to cardiac arrest and then sudden death.


Tachycardia or high heart rate is serious health condition that can be fatal. Heart rate above 100 beats per minute at rest in adults is tachycardia. When the heart rate exceeds 120 beats per minute, the heart rate should be restored soon.

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:May 18, 2018

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