Dangerous Heart Rate

Heart rate indicates the health of the heart and helps evaluate functioning of the cardiovascular system and overall health of an individual. Heart rate is described in beats per minute (bpm). With every beat, your heart pumps blood and fulfills the need of the body. The number of times your heart contracts in a minute or the number of times your heart beats in a minute is your heart rate. The rate keeps on changing while you perform various activities.

Normal Heart Rate

Hear rate measured when you are resting is your normal or resting heart rate (RHR). Infants, children, pregnant women have relatively higher RHR. Those who train their hearts and lungs with regular exercise exhibit low heart rate. A healthy heart beats slowly while pumping the required quantity of blood to body. Athletes and people engaged in sports have healthy hearts and so they have amazingly slow RHR. While exercising, body demands more oxygen (blood) and therefore heart has to beat faster to meet the demand of the body. In other cases, fast beating of heart indicates weakened heart muscle or lungs. Low heart rate is known as bradycardia and high heart rate is termed as tachycardia. Both these conditions can prove to be harmful for the heart and the body. Take a look at what is considered as the normal heart rate:

• For newborn infants: 100 - 160 bpm
• For children belonging to the age group 1-10 years: 70 - 120 bpm
• For children over 10 and adults (even elderly): 60 - 100 bpm
• For well-trained athletes: 40 - 60 bpm.

Tachycardia Causes

Heart rate beyond the normal range indicates problem in heart and so can be considered as dangerous heart rate. Tachycardia or bradycardia is noticed in various conditions. Common causes of tachycardia are listed below.

• Thyroid disorders
• Myocarditis, inflammation of the heart muscles
• Pacemaker not working
• Long term hypertension or high blood pressure
• Dysfunction of the heart valves leading to impaired blood circulation
• Pericarditis, inflammation of the pericardium, the fibrous sac that covers the heart
• Lack of oxygen to the heart muscles
• Coronary heart diseases
• Thickening of blood or other blood disorders
• Faulty atrium
• People who have survived one or more heart attacks are likely to experience tachycardia.
• Excessively high or very low sodium content in diet can lead to electrolyte imbalance resulting in tachycardia.
• Chronic obstructive pulmonary disease
• Strenuous physical activity

Bradycardia Causes

• Cardiac arrhythmia
• Partial or complete heart block
• Hormonal imbalance
• Under active thyroid
• Sick sinus syndrome
• Heat exhaustion
• Obstructive jaundice
• Vasovagal attack
• Yellow fever
• Supraventricular tachycardia
• Brucellosis
• Hypothermia
• Atrial flutter
• Electrolyte imbalance
• Side effects of certain drugs and medications, like overdose of anti-arrhythmic drugs, beta blockers, etc.

Unsafe Heart Rate During Exercise

Everyone notices high heart rate during exercise. Exercising with very high heart rate can damage your heart. It increases the risk of heart attack or cardiac arrest. You can note down your possible maximum heart rate (MHR) during exercise by performing a stress test on a treadmill (preferably in the presence of physician or physical trainer). Or if you are perfectly healthy, then you can use the following age adjusted formula to find out your MHR.

• MHR for women, during exercise = 226 - age
• MHR for men, during exercise = 220 - age

Those who are diagnosed with some diseases or those who are on medicines should consult their physician about possible MHR or heart rate during exercise. Once you know your MHR, you can start exercising with 50% of your MHR if you are a beginner. You can increase the hear rate during exercise gradually over months as your heart gets toned. Working with 50-60% of MHR is considered as working with safe heart rate. Since you cannot reap the health benefits of exercise if you work with very low intensity, you have to work with some intensity. Athletes and people who have chosen sports as profession undergo intensive training. They can work with 85% of MHR or even more as a part of circuit training or endurance training. But for normal people, it can prove to be dangerous. Your heart may go into fibrillation or working with very high heart rate can lead to partial heart block. If you are used to exercise, then you can work with 60-75% of MHR. This can be your fitness zone. Though working with 70-80% of MHR enhances the capacity of your heart and lungs, you should not try it at once. Athletes can exercise in this zone. You can feel breathless if you work with very high heart rate. Working in anaerobic zone or red line zone, even for a short while, should be avoided by normal people. Those who lead a sedentary lifestyle should take more care while exercising.

Dangerous is a relative term and so, dangerous heart rate can vary from person to person depending upon the age, sex, lifestyle, overall health of the person. I hope you found the above information helpful and you would take proper care during exercise.