Benign Heart Murmurs: Causes and When to Seek Care Explained

Key Takeaways

Benign heart murmurs are common and usually harmless.
They often result from normal changes in blood flow, not disease.
Medical evaluation is important if symptoms or concerns arise.

What Are Benign Heart Murmurs?

A benign heart murmur is a common finding that often causes concern but usually does not signal heart disease. These murmurs result from normal blood flow patterns and rarely require treatment or lifestyle changes.

Definition and Characteristics

A benign heart murmur, also called an innocent murmur, is an extra sound your doctor hears when listening to your heartbeat with a stethoscope. Instead of the usual “lub-dub,” you may have a soft whooshing or swishing sound caused by blood moving quickly through the heart.

These murmurs are not linked to structural problems. They occur when blood flow becomes slightly more turbulent than usual but still follows a normal pathway. Common triggers include fever, exercise, pregnancy, or rapid growth in children and teens.

Benign murmurs are usually:

Soft in sound (low intensity)
Short
Not associated with symptoms like chest pain or fainting
Variable, sometimes disappearing over time

Because they do not indicate disease, they typically require no treatment.

How Benign Heart Murmurs Differ from Abnormal Murmurs

Innocent murmurs differ from abnormal murmurs in both cause and clinical importance. An innocent murmur reflects normal blood flow, while an abnormal murmur often points to a problem with your heart valves or structure.

If your murmur is benign, you will not need restrictions on activity. In contrast, an abnormal murmur may require close monitoring and treatment depending on its cause.

Prevalence in Children and Adults

Innocent heart murmurs are especially common in children. As many as half of all children may have one at some point, often during growth spurts when blood flow is faster. These murmurs usually fade as the child grows and the heart matures.

In adults, benign murmurs occur less often but can still appear in certain situations. Pregnancy frequently causes temporary murmurs due to increased blood volume. Fever, anemia, or hyperthyroidism may also trigger them.

Most adults who develop a new murmur after age 40 will need further evaluation, since murmurs later in life are more often linked to valve disease. However, when your doctor identifies it as an innocent murmur, no treatment or long-term follow-up is needed.

Anatomy of the Heart and Murmur Formation

A murmur forms when blood moves through the heart in a way that creates extra sound. This usually happens when blood flow becomes turbulent as it passes through chambers or valves. Some murmurs are harmless, while others may point to structural problems.

Heart Chambers and Valves Involved

Your heart has four chambers: the right atrium, right ventricle, left atrium, and left ventricle. These chambers move blood in a set sequence, keeping oxygen-rich and oxygen-poor blood separated.

Between the chambers and major vessels are four valves:

Aortic valve (between the left ventricle and the aorta)
Mitral valve (between the left atrium and left ventricle)
Pulmonary valve (between the right ventricle and pulmonary artery)
Tricuspid valve (between the right atrium and right ventricle)

Valves open during the pumping phase and close tightly to prevent backflow. If valves do not open or close properly, blood flow becomes uneven and can produce a murmur. Even when valves are normal, increased flow through them may still create extra sound.

Blood Flow and Turbulence

Blood normally flows smoothly through the heart during systole (when chambers contract) and diastole (when chambers relax). This smooth flow is usually silent.

A murmur develops when blood becomes turbulent. Turbulence can occur for several reasons:

Narrowed or stiff valves
Leaky valves that allow backflow
Faster blood flow from conditions like fever, anemia, or pregnancy

Innocent or flow murmurs often happen when blood moves more quickly, but the valves and chambers are still normal. Abnormal murmurs, in contrast, usually point to valve disease or structural heart issues.

The loudness and timing of the murmur (systolic vs. diastolic) help doctors identify its cause. A diastolic murmur, for example, is more likely linked to a valve problem that requires further study.

Types of Heart Murmurs

Murmurs are classified by when they occur in the heartbeat and by their underlying cause.

By timing:

Systolic murmurs occur when the heart contracts
Diastolic murmurs:occur when the heart relaxes
Continuous murmurs: span both phases

By cause:

Innocent (functional or flow) murmurs: caused by faster blood flow without structural disease
Abnormal murmurs: linked to valve narrowing (stenosis), valve leakage (regurgitation), or defects in the heart walls

Doctors also grade murmurs on a scale of 1 to 6 based on how loud they sound with a stethoscope. This grading, along with the location and quality of the sound, helps determine whether the murmur is benign or needs more testing.

Causes of Benign Heart Murmurs

Benign heart murmurs often develop when blood flows more quickly or forcefully through the heart than usual. These murmurs are not linked to structural heart disease but instead result from normal body changes or temporary conditions that affect circulation.

Physiological Factors

Certain normal body states can increase blood flow and create a soft “flow murmur.” Pregnancy is one example, as your body produces more blood to support both you and your baby. This higher blood volume and cardiac output can cause a harmless murmur that usually disappears after delivery.

Exercise can also play a role. When you exercise, your heart pumps faster and harder to supply oxygen to your muscles. This temporary increase in blood flow may create a murmur, especially in people with otherwise healthy hearts.

Another factor is hyperthyroidism. An overactive thyroid speeds up your metabolism and raises your heart rate, which can produce turbulent blood flow. This change can result in a benign murmur, which often resolves once thyroid function is managed.

Temporary Conditions

Some short-term health conditions can lead to a benign murmur. Fever is a common cause because it raises your heart rate and increases circulation. As your body temperature returns to normal, the murmur usually fades.

Anemia is another condition that can cause this effect. With anemia, your blood has fewer red blood cells or less hemoglobin, making it less viscous. This thinner blood flows more quickly through the heart and vessels, producing a murmur that is not tied to heart disease.

Other temporary states, such as dehydration or mild illness, may also change blood flow patterns. These murmurs typically disappear once the underlying condition is corrected.

Growth and Development

Benign murmurs are especially common in children and teenagers. During rapid growth spurts, the heart and blood vessels adapt to new demands. This adjustment can create extra sounds as blood moves through the heart at a faster rate.

These murmurs are often soft, short, and may change when your child changes position, such as standing or lying down. They usually cause no symptoms and frequently go away as growth stabilizes.

In many cases, these developmental murmurs are first noticed during routine checkups. They rarely require treatment and are considered a normal part of growing up.

Recognizing Symptoms and Signs

Benign heart murmurs usually cause no health problems and often go unnoticed. In contrast, abnormal murmurs may point to underlying heart conditions that can produce noticeable symptoms and require medical attention.

When Benign Murmurs Are Asymptomatic

Most benign murmurs do not cause symptoms. You may feel healthy, have normal energy levels, and experience no limitations in daily activities. Doctors often discover these murmurs during routine checkups with a stethoscope, not because you reported any problems.

Innocent murmurs are common in children and young adults. They can also appear temporarily during pregnancy or periods of rapid growth, when blood flow increases. These murmurs are not linked to chest pain, fainting, or swelling.

Unlike pathological murmurs, benign murmurs do not cause shortness of breath or fatigue. You should not expect any physical signs such as bluish skin, ankle swelling, or irregular heartbeats. Because they are harmless, they typically require no medication or lifestyle changes.

The absence of concerning symptoms is the key feature of benign murmurs. If you feel well and your doctor confirms the murmur is innocent, no further testing is usually needed.

Distinguishing Features from Abnormal Murmurs

Abnormal murmurs often come with symptoms that signal an underlying heart issue. You may notice shortness of breath, especially when lying down or exercising. Some people experience chest pain or pressure that requires medical attention.

Other warning signs include swelling in the legs, ankles, or abdomen due to fluid buildup. Fainting or feeling lightheaded during activity can also indicate a more serious condition.

Doctors listen for differences in sound quality, timing, and intensity. Benign murmurs are usually soft and short, while abnormal murmurs may be louder, harsher, or continuous.

If you experience fatigue, palpitations, or sudden weight changes along with a murmur, your physician may order tests such as an echocardiogram. These tools help separate harmless murmurs from those caused by valve disease or structural heart problems.

Recognizing these distinctions helps you know when to seek further care and when reassurance is enough.

Diagnosis and Evaluation

A benign heart murmur is usually identified during a routine checkup. The process involves careful listening, targeted testing, and, in some cases, referral to a cardiologist to rule out underlying structural problems.

Physical Examination

Your doctor often detects a murmur while listening to your heart with a stethoscope. A benign murmur usually sounds soft, short, and does not radiate to other areas.

Doctors may ask you to change positions, such as lying down or standing, since the sound can vary with posture. They also check your pulse, blood pressure, and oxygen levels to look for signs of heart stress.

In children, growth and development are also reviewed. A healthy exam with no concerning symptoms often supports a diagnosis of an innocent murmur.

Diagnostic Tests Used

If the murmur is not clearly benign, your provider may order tests. An echocardiogram (echo) is the most common test. It uses sound waves to create moving images of your heart, showing how blood flows through valves and chambers.

An electrocardiogram (ECG) records the electrical activity of your heart. While it does not detect murmurs directly, it can reveal rhythm problems or chamber enlargement.

A chest X-ray may be used to view the size and shape of your heart. In rare cases, cardiac catheterization is performed if other tests do not provide enough detail. This procedure helps measure pressures and blood flow inside your heart.

Role of Cardiology Specialists

If your primary doctor suspects the murmur could be abnormal, you may be referred to a cardiologist. A cardiology specialist has advanced training in evaluating heart sounds and interpreting test results.

The cardiologist will review your medical history, family history, and symptoms such as shortness of breath, fatigue, or chest pain. They may repeat the physical exam with more detailed listening techniques.

Specialists also decide which imaging or monitoring tests are most appropriate. Their role is to confirm whether the murmur is harmless or linked to a valve or structural condition that requires treatment or follow-up.

When to Seek Care for a Heart Murmur

You should pay attention to new or worsening symptoms, follow your doctor’s advice for regular monitoring, and seek specialist care if your murmur is linked to a structural heart condition. Early evaluation helps determine whether the murmur is benign or associated with a condition such as valve disease or infection.

Warning Signs and Red Flags

Most benign murmurs cause no problems, but abnormal murmurs can point to underlying heart disease. You should seek medical attention if you notice shortness of breath, especially during activity or when lying flat.

Other important warning signs include:

Chest pain or pressure
Dizziness or fainting spells
Palpitations or irregular heartbeat
Swelling in your ankles, feet, or abdomen

These symptoms may signal conditions such as valve stenosis, mitral valve prolapse, or hypertrophic cardiomyopathy. Infections like endocarditis can also cause new or worsening murmurs, often with fever and fatigue.

If your lips or skin appear bluish, or you experience sudden weight gain from fluid retention, seek care right away. These are not typical of benign murmurs and may indicate heart failure or serious valve disease.

Monitoring and Follow-Up

If your doctor identifies your murmur as likely benign, you may not need treatment. However, regular checkups help ensure no changes develop over time. Your provider may use tools like an echocardiogram or electrocardiogram to track your heart’s structure and rhythm.

Children with innocent murmurs often outgrow them, but follow-up visits confirm normal growth and heart function. Adults may require closer monitoring, as valve problems, such as narrowing or leakage, can develop later in life.

You should report any new symptoms promptly. Even if your murmur has been stable, changes like fatigue, reduced exercise tolerance, or swelling can mean the murmur is no longer harmless. Consistent follow-up helps detect these changes before they become serious.

Referral to Cardiovascular Group

If your murmur requires further evaluation, your doctor may refer you to the Cardiovascular Group for specialized care. Cardiologists there can perform advanced testing, including detailed echocardiography, stress testing, and imaging to determine the exact cause.

You may need a referral if you are diagnosed with abnormal heart murmurs linked to valve stenosis, mitral valve prolapse, or hypertrophic cardiomyopathy. Patients with suspected endocarditis also benefit from early specialist involvement.

Specialists can recommend medical management, lifestyle adjustments, or procedures such as valve repair or replacement if needed. Even if your murmur proves benign, a cardiology consultation can provide reassurance and clear guidance for your long-term heart health.

Outlook and Living with Benign Heart Murmurs

A benign heart murmur, also called an innocent murmur, does not damage your heart or shorten your life. You can expect normal health outcomes, but you should still keep track of your heart health and understand when changes may need medical attention.

Long-Term Prognosis

Benign heart murmurs usually have an excellent outlook. They are common in children and often disappear as the heart matures. In adults, they may remain but rarely progress to disease.

You do not need treatment for an innocent murmur, and it will not affect your ability to exercise, work, or live a typical lifespan. Doctors may check it during routine visits, but no ongoing interventions are necessary unless new symptoms appear.

It is important to know the difference between an innocent murmur and one linked to valve disease. If you develop chest pain, shortness of breath, or fainting, you should seek medical advice. A benign murmur does not cause these symptoms but may signal another heart issue.

Regular checkups help confirm that your murmur remains harmless. Your provider may use a stethoscope or order an echocardiogram if there are changes in your exam or symptoms.

Lifestyle Considerations

You do not need to restrict your activities because of a benign heart murmur. You can safely exercise, play sports, and maintain a normal daily routine.

Focusing on heart-healthy habits supports your overall well-being. This includes:

Balanced diet with fruits, vegetables, lean proteins, and whole grains
Regular physical activity, such as walking, cycling, or swimming
Avoiding smoking and limiting alcohol intake

Pregnancy, anemia, or thyroid changes may sometimes make a murmur more noticeable, but these do not usually change its benign nature. Always let your doctor know about new health conditions so they can reassess your heart if needed.

You do not need special medications or procedures for an innocent murmur. Your main responsibility is to maintain healthy habits and stay alert for any unusual symptoms that point to a different heart problem.