Physiology of the Human Heart

The human heart, both physically and spiritually, is one of the most amazing creations in the universe.

As such, it's sad to me that the heart is also the leading cause of so many deaths in this country. Of the 2 million or so deaths every year, about 750,000 of them will have something to do with your cardiovascular system.

From the time we are in our mother's womb until we take our last breath, our heart—our most important muscle—tirelessly pumps.

Let's talk about how this incredible organ works, what it needs to function properly, and why everything you've been told about protecting it might be wrong.

The Structure of Your Heart

About the size of a fist, the average human heart weighs between seven and ten ounces. The heart is encased and protected by your rib cage, spinal column, and sternum.

The following three layers make up the outer wall of the heart:

1. The Epicardium (Outer Layer)

The outer layer is the epicardium or visceral pericardium since it is also the inner wall of the pericardium.

2. The Myocardium (Middle Layer)

The middle layer is the myocardium. It is composed of cardiac muscle and is what contracts.

This is the workhorse of your heart. This is where all the energy demand lives. The myocardium needs constant fuel to keep contracting 70-100 times per minute, 24 hours a day, every day of your life.

3. The Endocardium (Inner Layer)

The inner layer is the endocardium. It is in contact with the blood that the heart pumps. It also merges with the inner lining (the endothelium) of blood vessels and covers the heart valves.

How Blood Flows Through Your Heart

The human heart is a hollow, four-chambered muscle.

The right side of the heart (the right atrium and ventricle) receives deoxygenated blood from the body. The right atrium passes the blood to the right ventricle.

The right ventricle pumps blood through the pulmonary valve to the pulmonary arteries and into the lungs, where it becomes oxygenated.

That oxygen-rich blood then leaves the lungs through the pulmonary veins and goes into the left atrium. From there it is pumped through the mitral valve into the left ventricle, then on to the aorta through the aortic valve.

The oxygenated blood's long journey isn't over yet. It is pumped to every other organ in the body, except the lungs.

With each beat of your heart, your skin, brain, spleen, kidneys, and muscles are all getting oxygen.

And here's what most people miss: your heart pumps blood to itself via the coronary system of veins and arteries to provide oxygen to the myocardial muscle, so it can keep beating.

Your heart is a real workhorse.

Why Your Heart Needs Cholesterol (Yes, Really)

You've been told cholesterol clogs your arteries and causes heart attacks.

This is wrong. Cholesterol doesn't cause heart disease.

What your doctor didn't tell you: your heart muscle absolutely requires cholesterol to function.

Here's why:

Cholesterol Builds Cell Membranes

Every cell in your heart muscle is wrapped in a membrane made partially from cholesterol. Without adequate cholesterol, cell membranes become unstable and dysfunctional.

Your heart cells need intact, properly functioning membranes to:

• Regulate what enters and exits the cell
• Maintain electrical gradients (critical for heart rhythm)
• Support receptor function (how hormones communicate with heart cells)
• Protect against oxidative damage

Low cholesterol weakens cell membranes throughout your heart. This impairs function and increases vulnerability to damage.

Cholesterol Produces Hormones That Regulate Heart Function

Your heart function is regulated by hormones like testosterone, estrogen, progesterone, and cortisol.

All of these hormones are made from cholesterol.

Lower your cholesterol too much, and your body can't produce adequate amounts of these critical regulatory hormones.

This is one reason people on statins often report fatigue, weakness, and exercise intolerance. Their hearts can't produce the hormones needed to respond to physical demand.

Cholesterol Repairs Arterial Damage

When your coronary arteries (the arteries that feed your heart muscle) are damaged by inflammation, chronic stress, or high blood sugar, cholesterol arrives to patch the damage.

It's not causing the problem. It's trying to fix it.

For more on this, read: What Actually Causes Heart Attacks.

The Real Fuel Your Heart Needs: CoQ10

Your heart muscle has the highest energy demand of any tissue in your body. It never rests. It never stops contracting.

To meet this demand, your heart muscle is absolutely packed with mitochondria—the cellular powerhouses that produce ATP (energy).

And mitochondria require Coenzyme Q10 (CoQ10) to function.

CoQ10 is critical for the electron transport chain—the process that generates ATP inside your mitochondria. Without adequate CoQ10, your mitochondria can't produce energy efficiently.

This is why CoQ10 deficiency causes:

• Fatigue and weakness
• Exercise intolerance
• Shortness of breath
• Heart muscle weakness (cardiomyopathy)
• Heart failure

Your heart can't function without CoQ10. It's that simple.

How Statins Destroy Your Heart's Energy Production

Here's the cruel irony: statin drugs (prescribed to lower cholesterol and "prevent heart disease") block CoQ10 production.

Statins work by inhibiting an enzyme called HMG-CoA reductase. This enzyme is required to make cholesterol.

But HMG-CoA reductase is also required to make CoQ10.

Block the enzyme, and you block both cholesterol and CoQ10 production.

This is why muscle pain, weakness, and fatigue are the most common side effects of statins. Your muscles—including your heart muscle—can't produce the energy they need because you've depleted their CoQ10.

You're taking a drug to "protect your heart" that's actually starving your heart of the fuel it needs to function.

For more on this, read the upcoming post: Statins: The CoQ10 Theft (coming soon).

How to Support CoQ10 Levels Naturally

Your body makes CoQ10 naturally when you're young and healthy.

But production declines with age, stress, illness, and—critically—statin use.

To support CoQ10 levels:

Eat CoQ10-rich foods:

• Organ meats (heart, liver, kidney)
• Grass-fed beef and lamb
• Wild-caught fatty fish (sardines, mackerel, salmon)
• Pastured eggs

Supplement with ubiquinol: If you're over 40, under chronic stress, or on a statin, you need 100-200mg daily of ubiquinol (the active form of CoQ10).

Remove what depletes it: Chronic stress, blood sugar dysregulation, inflammatory foods, and statins all deplete CoQ10.

How to Actually Protect Your Heart

Heart health isn't complicated. But the pharmaceutical industry has made it seem complicated to sell you drugs you don't need.

Here's what actually works:

1. Move Your Body (But Not Too Much)

Your heart is a muscle. Like all muscles, it gets stronger with use.

But here's what most people get wrong: chronic high-intensity exercise damages your heart.

Marathon runners, chronic cardio addicts, and people doing intense CrossFit-style workouts 5-6 days per week are creating oxidative stress and inflammation that damages heart tissue.

Your heart needs balanced training: 80% low-intensity aerobic work (walking, easy cycling, swimming) and 20% high-intensity intervals (sprints, heavy lifting, explosive movements).

1-2 high-intensity sessions per week maximum. 3-5 low-intensity sessions per week.

This builds cardiovascular capacity without destroying it.

2. Balance Your Blood Sugar

The heart is a muscle. It contracts on average 70-100 times a minute, 24 hours a day, every day of your life.

If it skips even one beat, you usually know right away.

This muscle requires a steady stream of high-quality fuel. If you're constantly spiking and crashing your blood sugar with processed and refined carbohydrates, it's no wonder heart disease and dysfunction could be right around the corner.

The solution: balance your blood sugar by eating protein with non-starchy vegetables, getting rid of grains, and limiting fruit.

For comprehensive nutrition strategies, visit the Fuel Your Body pillar page.

3. Remove Inflammatory Foods (Especially Seed Oils)

Get all sugar, wheat, corn, dairy, and soy out of your diet.

These food sensitivities lead to inflammation that contributes to heart disease.

But the biggest dietary threat to your heart: industrial seed oils (canola, soybean, corn, vegetable oil).

These oils oxidize LDL cholesterol, damage arterial walls, and drive the inflammatory cascade that leads to plaque formation and heart attacks.

Remove them completely. Replace with olive oil, coconut oil, avocado oil, butter, and animal fats.

4. Manage Stress

Chronic stress elevates cortisol, which damages arterial walls, raises blood pressure, increases blood sugar, and drives inflammation.

Sleep 7-9 hours. Set boundaries. Say no. Meditate. Walk in nature.

For comprehensive stress management strategies, visit the Regulate Your System pillar page.

5. Play Once a Week

Find a hobby that is active and do it at least once a week. It can be anything from a martial art to rock climbing.

This isn't just about exercise. It's about joy, community, and doing something physical that doesn't feel like work.

Your heart benefits from movement. But it also benefits from dopamine, connection, and the kind of play that makes you feel alive.

6. Meditate and Pray

It doesn't matter what you believe. What's important is that you're present and mindful.

Most importantly, be grateful that you're here and alive, and you have the ability to experience life.

Gratitude and mindfulness lower cortisol, reduce inflammation, and improve heart rate variability—a key marker of cardiovascular health.

The Bottom Line

Your heart is an incredible organ. It beats about 100,000 times per day. It pumps about 2,000 gallons of blood daily. It never rests.

To do this, your heart needs:

• Cholesterol to build cell membranes, produce hormones, and repair damage
• CoQ10 to produce energy in mitochondria
• Stable blood sugar to provide consistent fuel
• Low inflammation to prevent arterial damage
• Balanced exercise to strengthen without destroying

Everything you've been told about heart health is backwards.

Lower cholesterol? Your heart needs it.

Take a statin? It depletes the CoQ10 your heart requires to function.

Avoid saturated fat? Your heart needs it for membrane structure and hormone production.

Do chronic cardio? You're creating oxidative stress that damages heart tissue.

The truth: cholesterol doesn't cause heart disease. Inflammation does.

Support your heart properly. Give it the cholesterol, CoQ10, stable fuel, and balanced movement it needs.

Your heart will thank you.

Want to optimize your cardiovascular health naturally? Dr. JJ Gregor provides comprehensive functional health evaluations at his Frisco, Texas practice. Schedule a consultation to understand your unique cardiovascular needs and develop a personalized strategy for heart health.