What is cardiac muscle?
Cardiac muscle tissue is one of the three types of muscle tissue in your body. The other two types are skeletal muscle tissue and smooth muscle tissue. Cardiac muscle tissue is only found in your heart, where it performs coordinated contractions that allow your heart to pump blood through your circulatory system.
Keep reading to learn more about the function and structure of cardiac muscle tissue, as well as conditions that affect this type of muscle tissue.
How does it function?
Cardiac muscle tissue works to keep your heart pumping through involuntary movements. This is one feature that differentiates it from skeletal muscle tissue, which you can control.
It does this through specialized cells called pacemaker cells. These control the contractions of your heart. Your nervous system sends signals to pacemaker cells that prompt them to either speed up or slow down your heart rate.
Your pacemaker cells are connected to other cardiac muscle cells, allowing them to pass along signals. This results in a wave of contractions of your cardiac muscle, which creates your heartbeat. Learn more about how your heart works.
What does cardiac muscle tissue look like when it moves?
Use this interactive 3-D diagram to explore the movement of cardiac muscle tissue.
What are heart muscles made of?
Intercalated discs are small connections that join cardiac muscle cells (cardiomyocytes) to each other.
Gap junctions are part of the intercalated discs. When one cardiac muscle cell is stimulated to contract, a gap junction transfers the stimulation to the next cardiac cell. This allows the muscle to contract in a coordinated way.
Like gap junctions, desmosomes are also found within intercalated discs. They help hold the cardiac muscle fibers together during a contraction.
The nucleus is the “control center” of a cell. It contains all of the cell’s genetic material. While skeletal muscle cells can have multiple nuclei, cardiac muscle cells typically only have one nucleus.
What is cardiomyopathy?
Cardiomyopathy is one of the main conditions that can affect your cardiac muscle tissue. It’s a disease that makes it harder for your heart to pump blood.
There are several different types of cardiomyopathy:
- Hypertrophic cardiomyopathy. The cardiac muscles enlarge and thicken for no apparent reason. It’s usually found in the lower chambers of the heart, called the ventricles.
- Dilated cardiomyopathy. The ventricles become larger and weaker. This makes it hard for them to pump, which makes the rest of your heart work harder to pump blood.
- Restrictive cardiomyopathy. The ventricles become stiff, which prevents them from filling to their full volume.
- Arrhythmogenic right ventricular dysplasia. The cardiac muscle tissue of your right ventricle is replaced with fatty or fiber-rich tissue. This can lead to arrhythmia, which refers to an abnormal heart rate or rhythm.
Not all cases of cardiomyopathy produce symptoms. However, it can sometimes cause:
- trouble breathing, especially when exercising
- swollen ankles, feet, legs, abdomen, or neck veins
It’s usually hard to pinpoint the cause of cardiomyopathy. But several things can increase your risk of developing it, including:
- a family history of cardiomyopathy or heart failure
- high blood pressure
- heavy alcohol consumption
- use of certain recreational drugs
- past heart attacks or heart infections
How does exercise impact cardiac muscle tissue?
As with many other muscles in your body, exercise can strengthen your cardiac muscle. Exercise can also help reduce your risk of developing cardiomyopathy and make your heart work more efficiently.
The American Heart Association recommends at least 150 minutes of moderate exercise per week. To reach this goal, try to get about 30 minutes of exercise five days a week.
As for the type of exercise, cardio workouts are named for their cardiac muscle benefits. Regular cardio exercise can help lower your blood pressure, reduce your heart rate, and make your heart pump more effectively. Common types of cardio exercises include walking, running, biking, and swimming. You can also try these 14 types of cardio exercises.
If you already have a heart condition, make sure to talk to your doctor before starting any kind of exercise program. You might need to take some precautions to avoid putting too much stress on your heart. Learn about the different signs of heart problems while exercising.
The bottom line
Cardiac muscle tissue is one of the three types of muscle in your body. It’s only found in your heart, where it’s involved in coordinated contractions that keep your heart beating. To keep your cardiac muscle working efficiently and to reduce your risk of cardiac conditions — including cardiomyopathy — try to get in some sort of exercise more days of the week than not.