Pulmonary hypertension (PH) is a cardiovascular condition that develops when increased blood pressure affects a person’s arteries in the lungs and the right side of their heart. For many people, PH develops over time and is chronic. However, in some people, the abnormal increase in blood pressure and other symptoms associated with PH occur only during exercise. Some doctors refer to this condition as exercise-induced PH.
Currently, it is unknown how common exercise-induced PH is because it can be difficult to diagnose. Many people with the condition may not have any symptoms other than fatigue during exercise, a symptom that may be ignored or dismissed. Additionally, exercise-induced PH has not been studied as extensively as other types of PH, such as pulmonary arterial hypertension (PAH).
Research is just beginning to focus on exercise-induced PH as its own type of PH, but some studies classify it as exercise-induced PAH. Notably, not all doctors agree whether exercise-induced PH represents a specific form of PH or if it’s an early stage of PH in people who already have risk factors for developing the condition.
Exercise-induced PH is characterized by an increase in blood pressure in the lungs during exercise. Blood pressure in the lungs is known as the mean pulmonary arterial pressure, (mPAP), which is measured in millimeters of mercury (mmHg).
At rest, a normal mPAP measurement is less than 20 mmHg. When exercising, people with no underlying PH or PH risk factors should typically have an mPAP measurement of less than 30 mmHg. (This number may be higher, however, in certain healthy patients without exercise-induced PH.) An abnormal mPAP is one that is greater than 30 mmHg during exercise.
Three factors contribute to a rise in pulmonary pressure with exercise:
The rise in pulmonary artery pressure alone does not define exercise-induced PH, as it also depends on the rise in both cardiac output and left atrial pressure. Therefore, health care professionals use a combination of measurements during exercise to make this diagnosis.
The increased pressure during exercise can affect blood flow through the lungs, limiting your exercise capacity (how long you can exercise). Exercise-induced PH can also affect your heart and cardiac output, which is how much blood the heart pumps and how much oxygen is used.
One of the first symptoms of exercise-induced PH is shortness of breath (known as dyspnea), especially during exercise. It is also common to feel fatigued during and after exercise. As the condition progresses, you may also experience shortness of breath at rest.
Currently, few studies have explored exactly how exercise-induced PH occurs, as it is just now gaining attention as potentially being its own condition. It is recommended that people who are at risk of developing PH should also be aware of exercise-induced PH.
Doctors believe that exercise-induced PH, like other types of PH, may be caused by certain underlying conditions, genetics, and more. These causes may include:
PH may also be idiopathic, meaning it has no known cause.
PH is diagnosed using several lung function tests that measure the pressure in your lungs’ arteries and your heart’s ability to pump blood. These tests can include spirometry, which measures how much air your lungs take in, and diffusion capacity, which measures how well oxygen enters your bloodstream.
Testing for exercise-induced PH can also include a stress test, an exercise echocardiogram, or an advanced cardiopulmonary exercise test (ACPET).
An exercise echocardiogram uses ultrasound testing to measure how well the heart is working during exercise. A small device, known as a transducer, is placed on the chest and sends sound waves to the heart and other organs in the chest. When the waves bounce off of the heart, they are reflected back and read by a computer that creates pictures of the heart.
Your doctor will likely use doppler echocardiography to look at the blood flow through the heart’s valves and chambers. This test will help doctors visualize how well your heart is working.
For an exercise echocardiogram, your doctor will typically take pictures of your heart at rest to use as a baseline. Then, you will begin exercising on a bike or treadmill, and continue until you begin to experience symptoms of exercise-induced PH. The doctor will then take another ultrasound and compare it to the baseline image to look for any differences between rest and exercise, which could suggest exercise-induced PH.
Although other tests can point to exercise-induced PH, an advanced cardiopulmonary exercise test is required to confirm the diagnosis. This test is also known as an invasive cardiopulmonary exercise test because it uses long, thin tubes, known as catheters, that are inserted into the right side of the heart and the pulmonary artery. A device attached at the end of the catheter is then able to measure oxygen use as well as heart and lung function. This test is similar to a right heart catheterization.
Once the catheter is in place, you will exercise for approximately 10 minutes while the device monitors your heart and lungs. Your doctor will use the data from the catheter to determine if you have exercise-induced PH or another condition that is causing your symptoms. ACPET is also used to diagnose:
After testing, your doctor will compare your results to diagnostic criteria known as the cardiopulmonary hemodynamic criteria. There are three criteria used to diagnose exercise-induced PH:
Another blood pressure measurement, pulmonary capillary wedge pressure, can also be used to diagnose exercise-induced PH. At rest, the pressure should be 15 mmHg, while during exercise, it will increase to 20 to 25 mmHg.
Treatment for exercise-induced PH is not well described because it has not been studied as much as other types of PH. One clinical trial conducted between 2009 and 2011 looked at using the drug ambrisentan (sold as Letairis) in people with systemic sclerosis and exercise-induced PH. Overall, the medication helped improve exercise-induced PH. This study had 12 participants. A second study involving 22 people also found the medication yielded similar positive outcomes.
Other medications typically used to treat PH that may help include:
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