Key takeaways

  • Many symptoms of hypertrophic cardiomyopathy (HCM) are mild, particularly in the early stages of the disease, so they may be easy to dismiss.
  • Symptoms such as shortness of breath during exercise, increased fatigue, and dizziness after standing up may be subtle signs of HCM.
  • Consult a doctor if you’re experiencing new or worsening symptoms such as these, especially if you have a family history of HCM.

Hypertrophic cardiomyopathy (HCM) is a genetic heart condition that causes the heart muscle — especially the left ventricle — to become unusually thick. This thickening can make it harder for your heart to pump blood efficiently. Research suggests that HCM affects about 1 in 500 adults worldwide.

HCM often goes undiagnosed, partly because its symptoms can be subtle and vary from person to person. Additionally, HCM does not have a specific defining symptom that you can watch for. Symptoms may develop at any stage of life and may worsen without a known cause.

Understanding the possible subtle signs of HCM could help you get an earlier diagnosis and prevent some complications of the disease. Below, we discuss some of these signs and how they might affect your daily life.

When you have HCM, the thickening of your heart muscle reduces the amount of blood that flows out of your heart. As a result, your heart needs more oxygen to work properly and pumps less blood throughout your body.

One possible effect of this reduced blood flow is that you might feel unexpectedly out of breath during routine activities.

You might find that you get winded during everyday activities such as walking, cleaning your home, or doing work-related tasks. You may even experience shortness of breath while resting or lying down.

If you consistently notice these symptoms, consider scheduling a medical appointment.

It’s not unusual for exercise to be tiring. But if you notice that exercise has become more exhausting than usual or you’re having trouble doing physical activities that used to feel easy, it could be a sign of HCM.

According to the National Organization for Rare Disorders, shortness of breath during exercise is the most common symptom of HCM.

In fact, some people with HCM experience symptoms only during exercise.

Shortness of breath during exercise is not always a sign of HCM. It might be a symptom of another health condition, such as anemia, lung disease or infection, fluid in your lungs, or a blood clot. In some cases, it might be caused by environmental conditions like weather changes or high altitude.

But if you notice a sudden change in your ability to exercise, don’t just write it off as a lack of fitness. Consider discussing it with a doctor.

Sometimes, a dizzy or lightheaded feeling after standing might just mean you stood up too quickly. But in some cases, it might indicate an issue with blood pressure or blood flow.

Unsteadiness, wooziness, and the feeling of nearly fainting can be other subtle signs of HCM.

If you frequently feel dizzy when changing positions or while exercising, consider consulting a healthcare professional. This is especially important if this symptom occurs alongside other symptoms such as heart palpitations (a feeling as if your heart is fluttering or skipping a beat) or fainting.

If you have less energy than usual, you might attribute it to aging, stress, or any of a host of other causes.

But a persistent feeling of tiredness or lack of energy is a common symptom of HCM, resulting from structural and functional differences in heart function.

If you have HCM, you might experience fatigue that limits your daily activities and doesn’t go away even after you’ve rested.

If you notice fatigue that’s new, worsening, or interfering with your usual activities, you may want to discuss it with a doctor.

Heart palpitations are another possible symptom of HCM.

Like fatigue and lightheadedness, heart palpitations are not always a cause for concern. But if you experience frequent or long-lasting episodes of a fluttering or irregular heartbeat, or if palpitations occur along with dizziness, fainting, or chest pain, it’s best to talk with a healthcare professional.

While it may be easy to write off symptoms such as fatigue, low exercise tolerance, and shortness of breath as common effects of aging or a lack of fitness, they could be signs of an underlying health issue.

Consider contacting a medical professional for an evaluation if you’re experiencing any of the following symptoms:

  • new or worsening shortness of breath
  • difficulty breathing during light physical activity
  • breathlessness during everyday activities
  • a gradual or sudden decrease in your energy level
  • symptoms that interfere with your ability to exercise
  • a need for longer recovery time after activities
  • dizziness during exercise or when changing positions
  • a sudden irregular heartbeat, especially during activity

Symptoms that are worsening or interfering with your daily life are a clear sign to seek help.

Call 911 or seek immediate medical attention if you experience symptoms such as fainting during or after exercise, severe chest pain, or sudden shortness of breath.

Because HCM is a genetic condition, it’s also a good idea to talk with a doctor if you have a family history of HCM — especially if you’re experiencing any symptoms. With proper management of HCM, many people live full, active lives.

Recognizing the symptoms of HCM could help you get an earlier diagnosis and reduce your chances of serious complications. While you might assume that certain changes in your body are simply due to aging or stress, some of those seemingly harmless symptoms may indicate a larger issue.

If you find that you’re more fatigued than usual or experiencing symptoms such as unexplained lightheadedness or a fluttering heart, consider making an appointment with a healthcare professional.