A heart murmur is often found during a routine physical examination, raising questions about what this extra sound means for a person’s health. The simplest explanation is that a heart murmur is not a feeling or a disease; it is an auditory event. It is a whooshing or swishing sound that a doctor hears using a stethoscope, distinct from the normal “lub-dub” of the heartbeat. This article clarifies why this sound typically produces no sensation and what symptoms may instead signal an underlying cause.
Defining the Heart Murmur
A heart murmur is caused by the turbulent flow of blood through the heart’s chambers, valves, or major vessels. Normally, blood flows smoothly (laminar flow), which is silent. When the flow becomes choppy, rapid, or rough, it creates vibrations audible as a murmur, similar to water rushing quickly through a constricted pipe.
The heart has four valves that direct blood flow. A murmur can arise if a valve is narrowed (stenosis), restricting forward flow, or if it leaks (regurgitation), causing blood to flow backward. Murmurs can also occur in a healthy heart when blood flows faster than usual, such as during exercise, fever, or pregnancy. Murmurs are classified based on their timing: systolic (when the heart contracts) or diastolic (when the heart fills).
Why Murmurs Don’t Typically “Feel” Like Anything
In the vast majority of cases, a heart murmur produces no physical sensation, meaning the person is completely unaware of its presence. Many murmurs are classified as “innocent” or “functional,” meaning they are not caused by a structural heart problem. They are simply the sound of normal, temporarily increased blood flow.
These innocent murmurs are common in children and adolescents, often disappearing or changing intensity with age or activity. Since they represent a normal physiological state, they do not cause internal symptoms or require treatment.
A rare exception involves very loud, high-grade murmurs (Grade 4 or higher on a 6-point scale). These can create powerful turbulence that causes a vibration strong enough to be felt through the chest wall. This palpable vibration, which a doctor detects with their hand, is medically termed a “thrill.” However, this sensation is a physical vibration felt externally on the body, not an internal feeling of the sound itself.
Symptoms That May Signal a Serious Underlying Cause
While the murmur sound itself is not felt, the underlying heart condition causing a pathological murmur can produce noticeable physical symptoms. These symptoms arise because the heart is struggling to pump blood effectively.
Common signs that the heart is struggling include:
- Shortness of breath, especially during physical activity or when lying flat.
- Chronic fatigue and weakness due to inadequate oxygenated blood reaching the tissues.
- Dizziness or fainting (syncope), signaling insufficient blood flow to the brain.
- Swelling (edema) in the legs, ankles, or abdomen as fluid backs up.
- Chest pain.
- A persistent cough that does not resolve.
- A bluish tinge to the skin or lips (cyanosis) in severe cases.
When to See a Doctor
Most heart murmurs are asymptomatic and are discovered incidentally during a routine physical examination. If a murmur is detected, the next step is to determine if it is innocent or pathological. This often involves diagnostic tests, such as an echocardiogram, which uses sound waves to create a moving picture of the heart’s structure and blood flow.
If you experience concerning physical symptoms—such as unexplained fatigue, difficulty breathing, dizziness, or swelling—seek medical evaluation immediately. You should also see a doctor if a previously identified murmur is present and you notice any change in your health status. The presence of a murmur warrants investigation to confirm whether it is a harmless sound or a sign that an underlying structural issue requires treatment.