Symptoms A-Z

Fainting After Exertion Symptoms, Causes & Common Questions

Understand your fainting after exertion symptoms, including 8 causes and common questions.

This symptom can also be referred to as: fainting while walking or running

Fainting After Exertion Symptom Checker

Take a quiz to find out what might be causing your fainting after exertion

8 Possible Fainting After Exertion Causes

The list below shows results from the use of our quiz by Buoy users who experienced fainting after exertion. This list does not constitute medical advice and may not accurately represent what you have.

Dehydration

Dehydration means the body does not have enough water to carry out its normal processes.

Most susceptible to serious dehydration are young children with fever, vomiting, and diarrhea. In adults, some medications increase urination and can lead to dehydration. Anyone exercising vigorously, especially in hot weather, can quickly become dehydrated.

Symptoms include extreme thirst; dry mouth; infrequent, dark-colored urine; dizziness; and confusion. Young children may have sunken eyes, cheeks, and soft spot on top of the skull.

Severe dehydration is a serious medical emergency that can lead to heat stroke, kidney damage, seizures, coma, and death. Take the patient to the emergency room or call 9-1-1.

Diagnosis is made through blood tests and urine tests.

Mild dehydration can be treated simply by drinking extra water, or water with electrolytes such as sports drinks. More serious cases may be hospitalized for intravenous fluids.

It's important for anyone who is outside in hot weather, or who is ill, to drink extra fluids even before feeling thirsty as thirst is not always a reliable guide.

Rarity: Rare

Top Symptoms: fatigue, dizziness, vomiting or diarrhea, racing heart beat, being severely ill

Urgency: Hospital emergency room

Right heart failure (cor pulmonale)

Acute cor pulmonale is also called acute right-sided heart failure and acute RHF. It is the sudden failure of the right ventricle of the heart.

The right ventricle pumps blood out of the heart, into the pulmonary artery, and into the lungs. If the pulmonary artery is blocked, the right ventricle will quickly become overworked and in danger of shutting down. A blood clot, called an embolism, or plaque lining this artery can suddenly cut off blood flow from the heart into the lungs.

Risk factors for acute cor pulmonale include surgery, obesity, smoking, and prolonged immobility. All of these leave the person prone to blood clots and/or plaque in the arteries.

Symptoms include sudden chest pain with rapid heartbeat, pale skin, cold sweat, shortness of breath, and coughing, sometimes with blood.

Acute cor pulmonale is a life-threatening medical emergency. Take the patient to the emergency room or call 9-1-1.

Diagnosis is made through physical examination, blood tests, echocardiogram, and chest x-ray.

Treatment involves oxygen, diuretics, blood-thinning and clot-dissolving medications, and sometimes surgery.

Rarity: Common

Top Symptoms: fatigue, chest pain, shortness of breath on exertion, wheezing, decreased exercise tolerance

Symptoms that never occur with right heart failure (cor pulmonale): severe chest pain

Urgency: Hospital emergency room

Narrowing of the aortic valve

Narrowing of the aortic valve is also called aortic valve stenosis, aortic stenosis, or AS. The aortic valve controls the flow of blood from the heart into the aorta, the body's main artery. If the aortic valve is abnormally narrow, the blood being pushed through it is blocked. Pressure may build up within the heart, causing damage.

AS may be caused by a congenital malformation of the valve, or by calcium deposits and/or the scarring that occurs as a person ages.

Symptoms may not appear right away. There will be chest pain with the feeling of pounding heartbeat, as well as shortness of breath with fatigue, lightheadedness, or even fainting.

It is important to see a medical provider for these symptoms, since AS can lead to stroke, blood clots, and heart failure.

Diagnosis is made through physical examination, echocardiogram, CT scan, and sometimes a stress test.

Treatment may simply involve monitoring and medication, while making lifestyle improvements in diet, exercise, weight, and smoking. Surgery to repair or replace the faulty aortic valve may be recommended.

Rarity: Uncommon

Top Symptoms: fatigue, shortness of breath, chest pain, shortness of breath on exertion, decreased exercise tolerance

Urgency: Hospital emergency room

Hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) means "abnormal thickening of the heart muscle." This can interfere with the heart's ability to pump blood.

Most often, an inherited genetic mutation causes HCM. However, aging, high blood pressure, diabetes, or thyroid disease can sometimes bring it about.

Many people have no symptoms at all. Some have unexplained chest pain, shortness of breath, fainting, or the feeling of rapid, fluttering heartbeat, because the abnormally thick heart muscle interferes with normal heartbeat and causes an arrhythmia. Take the patient to the emergency room or call 9-1-1.

Untreated hypertrophic cardiomyopathy can lead to serious heart disease and even sudden cardiac arrest and death, especially in people under age 30.

Diagnosis is made through echocardiogram; electrocardiogram; treadmill stress test; and/or cardiac MRI.

Treatment involves medication to relax the enlarged heart muscle and slow the rapid pulse. Surgery to remove some of the thickened muscle may be done, or a defibrillator may be implanted.

Anyone with a family history of HCM should ask their medical provider about screening for the disease, which involves regular echocardiography.

Rarity: Rare

Top Symptoms: fatigue, shortness of breath, dizziness, racing heart beat, shortness of breath on exertion

Urgency: Primary care doctor

Fainting After Exertion Symptom Checker

Take a quiz to find out what might be causing your fainting after exertion

Eisenmenger syndrome (tardive cyanosis)

Eisenmenger syndrome is a complication due to a heart defect. The defect causes increased blood flow to the lungs instead of the body.

Rarity: Ultra rare

Top Symptoms: shortness of breath, racing heart beat, shortness of breath on exertion, shortness of breath when lying down, decreased exercise tolerance

Urgency: Primary care doctor

Ebstein anomaly of the tricuspid valve

Many heart conditions are present from birth (congenital), and some can cause the valves to function improperly, resulting in symptoms such as poor blood circulation, fatigue, and difficulty breathing.

Rarity: Ultra rare

Top Symptoms: shortness of breath, racing heart beat, severe fatigue, lightheadedness, deep chest pain, behind the breast bone

Urgency: Primary care doctor

Carotid sinus syncope

Carotid Sinus Syncope is a pattern of fainting caused by abnormal response to touching the neck arteries (like tying a tie).

Rarity: Common

Top Symptoms: brief fainting episode, dizziness and lightheadedness before passing out, feeling nauseated, warm, and lightheaded before passing out, fainting after turning head to one side

Symptoms that always occur with carotid sinus syncope: brief fainting episode

Urgency: Hospital emergency room

Diabetic hypoglycemia

Hypoglycemia (severely low blood sugar) can occur in Type 1 (more common) and Type 2 Diabetes. It is usually caused by poorly timed use of blood-sugar-controlling medication.

Rarity: Uncommon

Top Symptoms: fatigue, irritability, anxiety, dizziness, racing heart beat

Symptoms that always occur with diabetic hypoglycemia: being severely ill

Urgency: Hospital emergency room

Questions Your Doctor May Ask About Fainting After Exertion

To diagnose this condition, your doctor would likely ask the following questions:

  • How long were you unconscious?
  • Did you injure your ear?
  • Have you ever been diagnosed with diabetes?
  • Have you noticed any vision changes?

The above questions are also covered by our A.I. Health Assistant.

If you've answered yes to one or more of these questions

Take a quiz to find out what might be causing your fainting after exertion

Fainting After Exertion Symptom Checker Statistics

People who have experienced fainting after exertion have also experienced:

  • 8% Dizziness
  • 5% Hip Weakness
  • 5% Rib Pain On One Side

People who have experienced fainting after exertion were most often matched with:

  • 33% Dehydration
  • 33% Right Heart Failure (Cor Pulmonale)
  • 33% Narrowing Of The Aortic Valve

Source: Aggregated and anonymized results from visits to the Buoy AI health assistant (check it out by clicking on “Take Quiz”).

Fainting After Exertion Symptom Checker

Take a quiz to find out what might be causing your fainting after exertion

Disclaimer: The article does not replace an evaluation by a physician. Information on this page is provided as an information resource only, and is not to be used or relied on for any diagnostic or treatment purposes.