Human Heart Rate

The human heart is a pump that circulates oxygenated blood in the body. Human heart rate is measured through the pulse, an essential unit that is used in all medical sciences.
The human heart is principally a pump that expands and contracts to pump the blood throughout the body. As an integral part of the respiratory and circulatory system the heart does an important function of forcing oxygenated blood from the lungs throughout the body and sends the de-oxygenated blood to the lungs to get oxygenated. To fulfill these two pumping functions, the heart contracts and then expands and contracts again. The total cycle of expansion, contraction and then getting ready for another cycle is known as a cardiac cycle and we know it as a heartbeat. The basic meaning of the term 'heart rate' is the number of such heartbeats or cycles or pulses per one minute. This rate is also known as a pulse rate. The following two paragraphs, elaborate upon two important facts, firstly, the cardiac cycle or what exactly takes place during a beat and secondly the simplest method that can be used to detect and measure such a heart rate.

The Cardiac Cycle

The heart rate indicates the pumping function of the heart. If you take a look at a labeled diagram of the heart, then you will be able to understand the following process and the anatomy of the organ.

The entire cardiac cycle is divided into three principle stages, namely, Atrial systole, Ventricular systole and Diastole. Among the three stages, the first two ones involve the major or important expansion and contraction of the heart while the third one involves the preparatory stage of the next heartbeat or pulse. So here goes...
  1. Atrial systole: The atrial systole is the stage of contraction. During the contraction, the Tricuspid valve opens up and de-oxygenated blood from right atrium goes into the right ventricular. On the other hand the Mitral valve opens up and oxygenated blood flows from left atrium to the left ventricle.
  2. Ventricular systole: The ventricular stage is the stage of expansion and outflow of blood from the ventricles. The oxygenated blood flows from left ventricle into the aortic valve and further into the aorta and then to the remaining parts of the body. In the right ventricle the de-oxygenated blood flows into the pulmonary artery, and then to the lungs for oxygenation.
  3. Diastole: In the last step, the atrium starts building pressure and blood starts gushing into the heart as it gets ready for another heartbeat.
This complicated cycle that takes place within a few nanoseconds, it is reason that we stay alive. Measuring the number of cardiac cycles is not that complicated.

Measuring the Heart Rate of a Human

Measuring the human heart rate is not that difficult from a layman's point of view, though there are several methods and formulas that have been developed, tried and tested by medical experts. Among these formulas that measure the heart rate of humans, range and its average, the HRmax, the Karvonen method and Zoladz method are commonly used.

From a layman's point of view, heart rate for humans can be measured with the help of the pulse rate. The heartbeat that we feel is during the ventricular systole and can be felt on many places throughout the body, the wrist, knee and neck being some of the common points. While measuring the pulse rates all you would have to do is lightly grip the point and count the pulses for exactly 60 seconds. The average adult normal pulse rate is about 72 give or take a few 10's. This unit is termed as BPM (beats per minutes) and the best BPM is 63.792. It must be noted that the normal heart rate is going to vary as per the activity you are doing and for the sake of convenience, medical practitioners, often take into consideration, a heart rate at rest.

Hypertension, young age (especially babies), athletes tend to have higher heart rates. Apart from that, abnormality, severe illness also causes the heart rate to drop. However, the diagnosis of such apart-from-normal heart rate can be done only by a medical probationer. This article is just a piece of information about the human body and if you are experiencing any abnormality in your heartbeat then please consult a doctor and ensure that you have a healthy heart.
By Scholasticus K
Published: 10/12/2010
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