Heart Beat Basics: The Electrical Side of Things


As a cardiologist, I like to say the fewer beats you use, the longer and better you live. What I mean by that is efficiency is key. Having a steady heart rate which moves blood through your body, allows nutrients to be delivered, waste to be removed and enhances overall function. An irregular heartbeat disrupts the delicate balance within our system, and this can cause dysfunction.

Today, we will discuss the electrical components of the heart, heart rate, and common disorders that affect the heart. Read on to learn more.

What is the Heart’s Electrical System?

Your heart is roughly the size of your fist, and it comprises four chambers. The upper chambers are the left and right atria. The lower chambers are the left and right ventricles.

The heart’s electrical system goes through a series of contraction and relaxation modes to pump blood through the heart’s atria and ventricles. Electrical impulses travel down a pathway in your heart and trigger your heartbeats. Your heart’s own pacemaker stimulates and regulates these electrical impulses, called the sinoatrial (SA) node.

How the Electrical System Makes your Heart Beat

Diastole: Part 1 of the Cardiac Cycle (contraction and relaxation of the heart)

When blood fills the upper chambers (right/ left atria) of your heart, it triggers the sinoatrial node to send an electrical impulse that tells the atria to contract. This contraction pushes the blood through the heart and into the lower chambers (right/ left ventricles).

Systole: Part 2 of the Cardiac Cycle

Now the lower ventricles fill with blood and electrical impulses signal the ventricles to contract. Valves open and blood flows from the ventricles into the lungs to pick up oxygen. Oxygen-rich blood is pumped into the left ventricle then flows to the rest of the body.

The blood transfers into the aorta, and then the ventricles relax and the valves close. This decrease in pressure (caused by the relaxation phase) causes valves to reopen and the cycle to begin again.

Each cycle (two phases) lasts roughly one second.

This cycle can increase contractions during exercise and decrease them during times of rest.

On average, the heart beats roughly 60-80 times per minute.

Your heart works with other parts of your body. Your brain senses your environment, your activity and your stress and then adjusts accordingly within the cardiovascular system.

The heart’s conduction system is like that of an orchestra. It has finely tuned movements of different sections that come together in the end for a well-produced symphony.  

Determining Heart Rate

The heart rate describes the frequency of the Cardiac Cycle. Each beat of the heart occurs in 5 main stages that depend on both contraction and relaxation of the heart muscle.

We define heart rate as the speed of your heart beat, and we measure it by the number of contractions that occur in your heart per minute (bpm).

On average, a normal resting heart rate is around 60-100 bpm. Usually, a lower heart rate at rest indicates good heart function and exceptional cardiovascular fitness. Again, the heart rate can vary depending on the body’s physiological needs.

Disorders That Affect Heart Beat

When the heart is functioning properly, most of us rarely think about it. We have an internal system which takes care of things like heartbeat, breathing, digestion, etc., but when there is a problem with our heart, we become very “tuned in.” 

Here are some things to make a note of:

  • Bradycardia: A heart rate slower than 60bpm
    • Athletes generally have lower heart rates. If you are in good physical condition AND feel good, this may not be an issue. However, if you are experiencing fatigue, lightheadedness, or shortness of breath with activity, contact your doctor.
  • Tachycardia: A heart rate that is faster than 100bpm
    • Some people may exhibit no symptoms, however, heart palpitations, an elevated pulse, and chest pain/tightness can be related to tachycardia.
  • Atrial fibrillation (AFIB): An erratic/irregular heartbeat
    • The inconsistency of this heart beat prevents the atria from contracting, so the heart does not push blood out. It then pools and stands still, disrupting blood flow. AFIB symptoms are often similar to tachycardia and need to be addressed.

The Takeaway

Think of your heart rate as being like the speed of your car. You don’t want your heart to beat too fast or too slow. You want it to beat at a nice and steady pace.

Support your heart’s natural beating pattern with a healthy diet and lifestyle. Drink plenty of clean water and make sure you are getting outside for some fresh air and sunshine.

If you need help, contact one of our health coaches today. They will support you on your journey. Be well.


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