The human heart is one of the most important organs in the body. It is responsible for pumping blood throughout the circulatory system. But what color is a healthy human heart? Many people assume the heart is red, since blood is red. However, the actual color of a healthy heart is not red at all – it’s white!
What Makes the Heart Appear Red?
The reason the heart appears red is due to the blood flowing through it. The chambers and vessels of the heart are filled with blood, which gives the organ its reddish hue. However, the muscle tissue itself that makes up the heart is not actually red.
The heart muscle, known as the myocardium, is striated muscle tissue like that found in skeletal muscles. The myocardium itself does not contain red blood cells or myoglobin, the protein responsible for the color of red muscles. Therefore, the actual heart muscle is white or pinkish-white in color.
The Color of a Healthy Heart
When a heart is exsanguinated – drained of its blood – its true color can be observed. An exsanguinated heart is white on the inside and outside. The heart only gains its reddish appearance when blood flows into the chambers, vessels, and capillaries that run throughout the organ.
During open heart surgery, the heart is stopped and drained of blood so surgeons can operate on the white, bloodless heart muscle. So while the heart pumps brilliant red blood when operating in the body, its normal color is actually white. The blood is what makes it look red.
Why the Heart Muscle is White
The main component of heart muscle tissue is cardiomyocytes, or heart muscle cells. Cardiomyocytes contain myofibrils, which are cylindrical contractile units made up of long protein chains. These myofibrils give the heart muscle its striped appearance under a microscope.
Cardiomyocytes do not contain myoglobin, the iron-rich protein that stores oxygen in muscles and gives them their red hue. While myoglobin is present in high amounts in skeletal muscles, allowing them to deliver oxygen even during contractions, it is not needed by the heart. The heart receives a constant supply of oxygenated blood through the coronary arteries so that myoglobin is unnecessary.
Other White Muscles
Like the heart, there are some other muscles in the body that do not appear red due to lower myoglobin concentrations. These include:
- Extraocular muscles – the muscles that control eye movement
- Muscles of the middle ear
- Muscles of the tongue
- Muscles of the larynx
- Diaphragm – the main muscle of breathing
- Muscles of the abdomen
Since these muscles all have constant or ready access to oxygen from blood circulation, they do not require oxygen-storing myoglobin and are white in color.
Changes in Heart Color
While a healthy heart is white, some diseases or conditions can cause the heart to appear different colors. These include:
- Cyanotic heart disease – Appears blue due to low oxygen levels
- Yellow fatty deposits – Due to high cholesterol
- Dark spots – Caused by clotting disorders
- White scar tissue – From previous damage or heart attack
- Orange – Caused by infections
Additionally, factors like diet, medication, and genetics can affect heart color over time and with age. The heart may gain a more yellowish or brownish appearance due to fatty plaque accumulation on the inner walls of blood vessels.
Testing Heart Health
While we cannot directly see the color of a living heart, doctors can use several tests to assess heart health and function:
| Test | What it Evaluates |
|---|---|
| Electrocardiogram (EKG or ECG) | Heart rhythm and electrical activity |
| Echocardiogram | Structure of the heart and pumping function |
| Stress test | How the heart works during physical exertion |
| Cardiac catheterization | Pressures within the heart chambers and blood vessels |
| Blood tests | Cardiac enzyme levels, cholesterol, etc. |
These tests allow doctors to detect any abnormalities in heart function or structure that could indicate disease. The results help determine appropriate treatment options and recommendations.
Protecting Heart Health
To keep the heart as healthy as possible:
- Do not smoke and avoid secondhand smoke
- Eat a diet rich in fruits, vegetables, whole grains, and lean proteins
- Limit sodium, sugar, saturated fat, and processed foods
- Maintain a healthy weight
- Control cholesterol and blood pressure
- Stay active with regular moderate exercise
- Manage stress levels
- Get enough sleep
- Have regular checkups with a doctor
Making heart-healthy lifestyle choices can reduce the risk of heart disease significantly, allowing the heart to keep pumping strong for years to come.
Conclusion
While the heart appears red when pumping blood, the muscle tissue itself is actually white in color. This is because the myocardium does not contain myoglobin like skeletal muscles do. A healthy heart gains its red hue from the blood flowing through it, not from the color of the muscle itself. Knowing the true color of the heart helps us understand its anatomy and function more accurately.