Signs and Causes of a Weakened Heart Muscle

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In a healthy heart, blood is pumped from the right side of the heart to the lungs, where it picks up oxygen. It is then pumped out of the left side of the heart to supply the body with oxygen and vital nutrients. Any condition that interrupts this two-chamber system can cause heart failure

Many conditions can cause the heart to weaken. When the heart is weak, it is unable to pump enough blood to meet the body’s needs. Conditions like diabetes, coronary heart disease, and high blood pressure damage or cause the heart to overwork, which can lead to heart failure.

Over time, these conditions weaken the heart, rendering it unable to either fill up properly (a condition called diastolic heart failure) or pump efficiently (a condition called systolic heart failure). 

Learn more about the signs and causes of a weakened heart muscle.

doctor listening to person's heart

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Signs of a Weakened Heart Muscle

When the heart is weakened, it tries to compensate by pumping quicker, which can stretch the heart or thicken the heart muscle. Both of these compensatory mechanisms further weaken the heart.

If the kidneys sense low blood flow, they stimulate fluid retention. This causes the heart to work harder, worsening the problem even more. 

Signs and symptoms that may be warning signs of a weakened heart muscle include:

  • Shortness of breath (also known as dyspnea), particularly when you lie down or exert yourself
  • Chest pain, especially a heavy sensation in your chest indicative of heart failure caused by a heart attack
  • Fatigue 
  • Swelling of the legs, ankles, and feet (also known as edema)
  • Rapid or irregular heartbeat
  • Exercise intolerance
  • Persistent cough or wheezing with white or pink blood-tinged phlegm
  • Persistent urge to urinate (also known as polyuria)
  • Swelling of the abdomen (also known as ascites)
  • Unexplained, rapid weight gain
  • Lack of appetite
  • Nausea
  • Difficulty concentrating

Causes

Weakening of the heart usually occurs because the body is trying to compensate for a failing heart. Although the body’s ability to compensate may be beneficial initially, for the failing heart these adaptations often contribute to the most serious cases of heart failure in the long run.

Narrowing of the Arteries

Hardening and narrowing of the arteries is another name for the medical condition, atherosclerosis, which occurs when cholesterol and other substances build up in the walls of arteries and form hard structures called plaques.

Coronary artery disease (CAD) is the result of severe atherosclerosis and becomes a problem when the blood that is pumped out of the heart is not enough to support bodily functions. Blood not only supplies the heart with oxygen, but also provides vital nutrients that are key to the heart’s proper functioning.

Over time, CAD can weaken the heart muscle and contribute to heart failure and arrhythmias.

High Blood Pressure

High blood pressure forces your heart to work harder to pump blood. More forceful pumping of the heart leads to a thickening of the muscle, specifically the left ventricle, which can increase your risk of:

Chronically high blood pressure—that is, a sustained blood pressure above 120/80 for adults—also narrows the arteries and enlarges the heart, compromising the structural integrity of the heart muscle. An enlarged and weakened heart cannot pump blood efficiently throughout the body, making it impossible to meet the body’s demands for oxygen and nutrients.

Obesity

Obesity is a growing health problem worldwide.

On the one hand, it increases cardiovascular risk because the body requires more blood to supply oxygen and nutrients to vital tissues and organs. In order to meet this need, the body increases blood pressure to meet the body’s demands.

On the other hand, obesity is associated with several medical conditions that put you at higher risk of heart disease, including:

Obesity may also increase atherosclerosis and contribute to structural and functional changes of the heart, which weaken the heart. The altered myocardial structure of the heart muscle increases the risk of atrial fibrillation and sudden cardiac death.

Of note, obesity is mostly but not entirely bad. Some studies have shown that overweight and mild levels of obesity may have a protective effect on the clinical outcome of some underlying cardiovascular diseases, a phenomenon called the obesity paradox.

Smoking

When you inhale, fresh air oxygen is taken in to replenish the blood. When you smoke, that air is contaminated. The carcinogenic chemicals in cigarette smoke not only damage the lungs, which are integral to the cardiac cycle, but also the heart muscle, increasing your risk of cardiovascular disease.

In addition, chemicals in cigarette smoke change your blood chemistry, leading to atherosclerotic changes such as blood vessel narrowing and plaque formation. These can permanently damage your heart and blood vessels.

Congenital Heart Defects

Congenital heart defects are structural problems of the heart that are present at birth and may change the way the heart works.

A normal heart has valves, arteries, and chambers that circulate blood in a cyclical pattern: body to heart, heart to lungs, lungs to heart, and then heart out to the body. When this pattern is thrown off, it can cause the underdeveloped heart to change shape and function less efficiently. Pressure can build and the heart muscle can weaken and fail as a result.

Congenital heart defects range in severity from small holes between chambers to the complete absence of one or more chambers or valves. The greater the severity of the congenital heart malformation, the greater the likelihood of developing a weakened heart and long-term complications. 

Lifestyle Factors

Lifestyle factors are the single most important cause of a weakening heart. This also means that heart disease may be preventable for many people. To help keep the heart strong:

  • Quit smoking
  • Eat a healthy diet
  • Engage in routine physical exercise from a young age

The impact of your lifestyle on your heart health is complex and multifactorial in nature.

For example, the chemicals in cigarette smoke not only weaken the heart muscle directly, but also increase atherosclerosis. Even worse, research has shown that those who engage in one unhealthy habit are also more likely to be overweight or obese and have high blood pressure.

We now know that sedentary lifestyle, heavy alcohol use, poor diet, and obesity add further strain to the heart. As pressure builds up in the heart, the heart muscle can thicken and lose its ability to pump effectively.

The key to a heart-healthy life is to implement health-positive habits early in life and sustain them throughout the life course.

When to See a Doctor

Signs and symptoms of a weakened heart may be subtle and therefore easily missed or inadvertently associated with a more benign condition like normal aging.

If you wait until you experience obvious symptoms of heart failure before seeing a healthcare professional, the condition may already be life threatening. If you experience any of the aforementioned symptoms, seek immediate medical attention.

Treatment

Most often, a weakened heart muscle is caused by coronary artery disease or heart attack, but faulty heart valves, long-standing high blood pressure, and genetic disease may also be to blame. And sometimes, more than one condition may play a role in your weakening heart.

Treating the underlying cause of your weakening heart is the best way to mitigate symptoms and improve your activity level. Treatment options include:

  • Engaging in regular low-intensity aerobic exercise to strengthen the heart
  • Eating a heart-healthy diet
  • Cutting back on salt (sodium)
  • Limiting your alcohol consumption
  • Quitting smoking

The use of one or several medications aimed at reducing the fluid load on the heart may further help. These include:

  • Diuretics, which help reduce fluid buildup in the body
  • Angiotensin-converting enzyme (ACE) inhibitors, which help lower blood pressure and reduce strain on the heart. If you cannot tolerate ACE inhibitors, angiotensin receptor blockers (ARBs) may be used in their place.
  • Beta-blockers, to reduce the heart rate and blood pressure
  • Sodium-glucose co-transporter 2 inhibitors (SGLT-2), which are a treatment for diabetes but also improve outcomes in people with heart failure
  • Ivabradine (Corlanor), to reduce the heart rate
  • Digoxin (Lanoxin), which lowers the heart rate and strengthens heart contractions

Prevention

Blood Pressure Control

The goal of a heart-healthy lifestyle is to keep your blood pressure around 120/80 mmHg. This ensures that your heart is not overworking itself. Maintaining healthy blood pressure also lowers the risk of the following:

  • Stroke
  • Kidney failure
  • Vision loss
  • Sexual dysfunction
  • Angina due to coronary artery disease

Eat a Healthy Diet

Eating a balanced diet that is full of fruits and vegetables, whole grains, nuts, fish, poultry, and vegetable oils is the best way to prevent heart disease.

Limiting red meat, refined carbohydrates, highly processed foods, and alcohol also goes a long way in keeping your heart healthy.

Studies have shown that the Mediterranean diet and plant-based diets—which are high in whole grains, vegetables, fruits, legumes, and nuts—are particularly heart-healthy and lower the risk of heart disease by as much as 20%.

Maintain a Healthy Weight

Some studies have found that waist size and excess weight—markers of obesity—are the single biggest risk factors for coronary artery disease.

Of note, the COVID-19 pandemic has led to rapid increases in weight and may contribute to future increases in cardiovascular disease. 

Exercise

The U.S. Preventive Services Task Force recommends 30 minutes of moderate-intensity physical activity five days a week to prevent heart failure. Exercising keeps the heart strong and helps the blood to circulate optimally, counteracting the effects of aging on the cardiovascular system to some degree.

Getting in regular physical activity has so many benefits, such as lowering the risk of:

  • Heart disease
  • Diabetes
  • Stroke
  • High blood pressure
  • Osteoporosis
  • Certain cancers

Not to mention, exercise has the added benefits of:

  • Controlling stress
  • Improving sleep
  • Maintaining a healthy weight
  • Reducing the likelihood of developing cognitive decline later in life 

Monitor Drug Interactions

It is not uncommon for those with heart failure to take multiple medications. While managing your symptoms of heart failure may require that you take more than one medication, several commonly used prescription drugs, over-the-counter medicines, and supplements can interact dangerously, intensifying heart failure symptoms and putting you at risk of developing life-threatening complications.

To be on the safe side:

  • Make sure all of your medical providers have a complete list of all the medicines you take.
  • Do not begin a new medication without first checking in with a healthcare professional.
  • Be mindful of the symptoms that may arise with each new medication. If you experience worsening or new symptoms, stop the medication immediately.

Some common medications to watch out for include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs)—common over-the-counter painkillers like ibuprofen (Advil, Motrin)—can cause the body to retain sodium and fluid, worsening heart failure symptoms.
  • Heartburn medicines and cold remedies contain sodium, which stimulates fluid retention. 
  • Herbal remedies like ephedra, St. John’s wort, ginseng, hawthorn, black cohosh, and green tea can interact and lessen the effects of several common heart medications.

Summary

Many conditions can cause the heart to be weakened. If you experience any symptoms of a weakened heart muscle, see your doctor as soon as possible.

A Word From Verywell

Never ignore any heart symptoms.

If you are feeling more fatigued than usual, unusual aches and pains, lightheaded, or have chest pain, seek immediate medical attention.

While many conditions merely mimic the classic signs of a weakened heart muscle, it is better to be safe than sorry. Even if your symptoms do not signal immediate danger, they may be a warning sign of a larger problem down the line. Addressing these signs quickly can mitigate long-term complications, especially for those more than 60 years old.

As you get older, eating a heart-healthy diet is essential, but we acknowledge that making or sticking to these changes isn’t always easy. Do not become discouraged. The tradeoff of living a heart-healthy life is well worth it.

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