Introduction

The heart is a muscle that grows in size and shrinks according to the circumstances of the body.

The heart has plasticity. It shows an increase in size as a response to some stimuli, such as an increase in blood pressure, aortic stenosis (thickening and narrowing of the aortic valve), and mutation of certain genes that can also lead to enlargement of the heart.

However, heart enlargement is not always pathologic sometimes it is a natural process as seen in pregnancy, exercise, and after meals. These physiologic stimuli can increase the size of the heart by up to 20%.¹

Whenever the heart is enlarged as a disease, not due to physiologic stimuli, It challenges the body to provide more oxygen and nutrients to function properly.

Understanding Heart Enlargement

Definition and types 

An enlarged heart is not a positive condition as it may sound. When the heart increases in size, it causes certain changes in the circulation. These changes can either decrease the efficiency of the heart or increase the load in the whole circulation rendering the blood capacity to carry oxygen insufficient.²

Dilated cardiomyopathy 

Dilated cardiomyopathy is a type of heart disorder, it is a non-ischemic heart disease (is not caused by lack of blood supply). It is rather a disorder in both the function and the structure of the heart.³

In dilated cardiomyopathy, the left ventricle of the heart or both ventricles are dilated. In addition to a dysfunction in the ability of the heart to pump blood.

Several associations describe dilated cardiomyopathy but they all agree that it happens either due to genetic mutation or due to some acquired causes.³ These abnormalities can lead to multiple complications and eventually death.

Hypertrophy

Hypertrophy of the heart is another type of heart enlargement. It occurs due to either external stimuli like alcohol abuse or internal stimuli like ischemia and hypertension. 

These factors lead to an increase in the size of the heart in its trial to keep up with the required effort. Although hypertrophy can, to a certain limit, make the heart able to cope with the demand, it is an unfavourable response of the heart as it might lead to heart failure. People with hypertrophied hearts are at an increased risk of sudden death.⁴

Common causes (e.g., high blood pressure, valve diseases)

Many factors can lead to the enlargement of the heart:

• Anemia: when the number of healthy red blood cells carrying oxygen decreases, the heart tends to work harder to compensate for this shortage leading to an increase in the size of the heart
• Pregnancy: a pregnant woman’s heart supports two bodies, so the heart increases in size temporarily. In this case, it is considered a physiologic change
• Sleep apnea: the restlessness can cause the heart to overwork itself and eventually enlarge
• Hypertension (increased blood pressure): a patient’s heart with chronic hypertension tends to work hard specifically the left ventricle of the heart leading to an increase in the thickness of its wall 
• A previous heart attack can cause damage to the tissues of the heart which will lead to an increase in the size of the heart to cope with the demands of the body
• Heart valve diseases: when a certain valve thickens or becomes narrow, the corresponding chamber tends to enlarge to cope with the extra effort
• Irregular heartbeats put pressure on the heart leading to its enlargement²
• Alcohol consumption leads to dilated cardiomyopathy.Deaths caused by cardiomyopathy in alcoholic people represent 6.9% in men globally and 2.9% in women³

Other causes of heart enlargement but not common are bradycardia (decrease in heart rate), an elevation of the diaphragm, a depression of the sternum, or a pericardial disease (a disease affecting the layer surrounding the heart).⁵

Symptoms and diagnostic methods

• Shortness of breath, regardless of the type of activity done
• Dizziness and fainting
• Persistent fatigue
• Swelling in feet, ankles, or legs
• Coughing, which  increases when the patient lies down
• Palpitations (increased heartbeats)

These symptoms are evident when the increase in the heart size is moderate or severe.⁶

This condition is diagnosed with chest X-rays, echocardiogram, CT scans, ECG, and MRI. 

The Role of Exercise in Heart Health

Benefits of exercise for cardiovascular health

The American Heart Association has stated five major risk factors immensely affecting cardiac health or worsening cardiovascular diseases like obesity and smoking. One of these major risk factors is leading a sedentary lifestyle with no evidence of physical activity.

Changing a sedentary lifestyle into an active one, even if the physical activity is merely brisk walking, can have positive effects on one’s cardiac health and reduce the possibility of experiencing another heart attack or stroke.

Regular exercise can cause a positive change in the overall health of the patient and the cardiac health as well. It reduces weight, which leads to a reduction in blood pressure and the level of bad cholesterol, and raises the levels of good cholesterol. It increases the insulin sensitivity in the body which helps with sugar levels in the blood.⁷

The American College of Sports Medicine, along with the Centers for Disease Control and Prevention, encourages adults to enroll in moderate-intensity exercise for at least 30 minutes a day. These activities include swimming, cycling, house chores, or brisk walking.⁷

Special considerations for individuals with heart conditions

There are risks related to cardiac health that anyone who is exercising is prone to. For instance, experiencing a disorder in the heart rhythm or a heart attack. However, the chance to experience such an event is minimal. For people who don't suffer a cardiac problem, the chance of suffering a cardiac problem is 1 in 400,000-800,000 hours of exercise, while for a cardiac patient, the risk increases to 1 in 62,000 hours of exercise.⁷

However, a cardiac patient who does not exercise at all is 50 times more prone to have a cardiac event than a cardiovascular patient who exercises regularly.⁷ Additionally, 90% of cardiovascular patients who experience a heart attack are usually at rest.⁷

Regular exercise is beneficial for a patient with a heart condition, but training intensities should be adjusted according to their health conditions and done under supervision.

Risks of Overexertion for People with Heart Enlargement

Increased Strain on the Heart

Heart strain is a condition that results from extreme or prolonged exertion. This extreme exertion causes sudden symptoms to affect the aorta and heart.⁸ As a result, physical disabilities may occur.

Elevated blood pressure and heart rate

At the beginning of the 20th century, patients with heart problems were advised to rest. But recent studies have proved that it is more beneficial to exercise than to rest.

Exercise training is now an important part of the rehabilitation of patients with cardiovascular diseases. In the long run, exercising regularly can improve both the function and the structure of the heart. Exercises that are considered dynamic increase heart rates and blood pressure. However, in old patients, these increases can be exaggerated and cause complications. Moreover, these exercises increase the output of the heart from 20% at rest to 85%, which puts more load on an enlarged heart. 

Exercises that train small muscles without the need for movements are more beneficial for people with an enlarged heart as they increase the resistance of blood vessels, and increase blood pressure without demanding a significant increase in the cardiac output or oxygen demand.⁹

Signs of Overexertion to Watch For

As previously mentioned, exercise is indeed beneficial, but there are some signs and symptoms you should watch for, so stop training immediately and seek medical help.

These signs are:

• Chest pain
• Jaw or neck pain
• Referred pain in the shoulder or arm
• Shortness of breath
• Abnormal heartbeat
• Dizziness 

Safe Exercise Practices for Individuals with Heart Enlargement

Exercises that don’t increase the load on the heart or oxygen demand and still cause the blood circulation to move more and burn more calories are demanded for patients with cardiac problems. Some dynamic exercises can decrease blood pressure whether resting or ambulatory blood pressure. These exercises should be done under professional supervision and with doctors' recommendations.⁸