Cardiac imaging may be needed when a runner has symptoms such as chest pain during exercise, fainting or near-fainting, new racing heartbeats with dizziness, or breathlessness that seems out of proportion to the effort. A clinician first reviews the timing of symptoms, medical and family history, examination, and often an ECG. An echocardiogram, stress test, cardiac MRI, or CT scan is chosen only when it can answer a specific question.
Which symptoms may prompt cardiac imaging in runners?
Running makes the heart work harder, so symptoms that appear during exercise can provide important information about cardiovascular health. Some experiences are related to normal physical exertion, but new, unexplained, persistent, or recurring symptoms deserve medical attention, particularly when they begin during a run or limit a runner's usual ability to exercise.
Examples of symptoms that may lead a healthcare professional to consider further heart testing include:
- Chest pain or pressure during exercise: Discomfort that appears while running, particularly if it repeatedly occurs with exertion, may require evaluation for a heart-related cause.
- Fainting or nearly fainting: Losing consciousness during a run or feeling as though consciousness is about to be lost can require prompt assessment, especially if the episode occurs while the person is still exercising.
- Sudden or unusual palpitations: A racing, pounding, or irregular heartbeat may deserve further investigation when it begins abruptly or occurs with chest discomfort, dizziness, or fainting.
- Unusual shortness of breath: Breathlessness that is unexpected for the level of effort, limits normal training, or occurs alongside other concerning symptoms may prompt a cardiac evaluation.
- A noticeable change in exercise capacity: A new inability to maintain a previously comfortable pace, especially when accompanied by other symptoms, may lead a clinician to investigate the heart as well as other possible causes.
These examples help explain when an evaluation may be useful; they are not a checklist for identifying a heart condition. The timing of symptoms, whether they stop after exercise, associated experiences, medical history, and examination findings all influence the next steps.
When is cardiac imaging particularly important?
Imaging becomes especially relevant when a clinician needs to assess the heart's structure, pumping function, valves, or blood supply. The decision often follows an initial assessment that includes a medical history, physical examination, and electrocardiogram (ECG), which records the heart's electrical activity.
Fainting during exercise deserves particular attention. The Heart Rhythm Society's 2024 expert consensus on arrhythmias in athletes recommends an ECG, exercise stress test, and transthoracic echocardiogram for athletes who experience syncope during exertion. If initial testing does not explain the episode and concerning features remain, additional imaging may be needed.
The American Heart Association and American College of Cardiology's guidance on competitive sports participation also emphasizes comprehensive evaluation when fainting during exercise occurs with features that raise concern for structural or electrical heart disease. These findings can influence whether further imaging is needed and whether competitive training should pause during the assessment.
Which cardiac imaging tests might a runner need?
There is no single scan that is best for every runner. Each test answers different questions, and the clinician selects it according to the symptoms and the possible cause being investigated.
1. Echocardiogram: Checking the heart's structure and function
An echocardiogram uses sound waves to create moving pictures of the heart. It allows clinicians to examine the heart's chambers, valves, pumping function, and blood flow. It may help identify structural abnormalities or problems with the heart muscle or valves that could be relevant to exercise-related symptoms.
According to Mayo Clinic's information on echocardiograms, this test can help assess valve disease, certain conditions present from birth, and changes in heart-wall movement. However, a standard echocardiogram does not directly show every narrowing or blockage in the coronary arteries, so another test may be needed when blood supply is a concern.
2. Exercise stress testing: Assessing the heart during exertion
An exercise stress test monitors the heart while a person exercises on a treadmill or stationary bicycle. The healthcare professional may monitor the ECG, heart rate, blood pressure, and symptoms as the workload increases. The goal is to look for changes that might not be evident when the person is resting.
Mayo Clinic's guidance on coronary artery disease testing explains that exercise stress testing may be useful when symptoms typically occur during physical activity. In some cases, stress testing is combined with imaging, such as an echocardiogram, to examine how the heart responds to exertion.
For runners, the reported activity and symptoms help the clinician decide how an exercise test should be conducted. Someone who has fainted, experienced chest pain, or developed significant symptoms during exercise should not try to reproduce those symptoms through an unsupervised hard workout.
3. Cardiac MRI: Obtaining more detailed images
Cardiac magnetic resonance imaging (MRI) uses a strong magnetic field and radio waves to produce detailed pictures of the heart. It can provide information about heart-muscle structure, tissue changes, inflammation, scarring, and function. A clinician may request it when initial findings suggest a problem that requires a closer look or when other tests have not adequately explained the symptoms.
The Cleveland Clinic's cardiac MRI guidance describes its use in evaluating heart symptoms and conditions affecting the heart muscle, valves, and other structures. MRI may be particularly useful when a more detailed assessment of suspected cardiomyopathy or heart-muscle injury is needed.
4. Cardiac CT or coronary CT angiography: Examining the heart's arteries
Cardiac computed tomography (CT) creates detailed images using X-rays. A coronary CT angiogram uses contrast material to show the coronary arteries, which supply blood to the heart muscle. Depending on the clinical question, these tests may help assess coronary artery narrowing or identify certain structural features, including an unusual origin or course of a coronary artery.
CT is not automatically necessary whenever a runner has chest discomfort. The clinician considers the person's age, cardiovascular risk factors, symptoms, and earlier test results before choosing it. CT involves radiation, and coronary CT angiography generally requires contrast material, so its potential benefit and limitations should be considered for each person.
How do age and medical history affect the decision?
The possible causes of exercise-related symptoms and the usefulness of particular tests can differ with age and background. In children, teenagers, and younger adults, clinicians may consider structural abnormalities present from birth, inherited heart-muscle conditions, and disorders affecting the heart's electrical system. An echocardiogram, cardiac MRI, or coronary CT may be considered when the clinical findings justify a closer assessment.
For middle-aged and older runners, coronary artery disease may receive greater consideration, especially when there are relevant cardiovascular risk factors or symptoms suggestive of reduced blood flow to the heart. The clinician may choose an exercise test, stress imaging, or coronary imaging depending on the specific concern. Age alone does not determine which scan is required.
A personal history of heart disease, previous unexplained fainting, or a family history of early or unexplained sudden death can also influence the evaluation. Recent changes in training performance, medications, supplements, and the exact circumstances of an episode may help the healthcare professional decide whether imaging or another form of testing is appropriate.
What happens if the first tests do not explain the symptoms?
A normal initial ECG or echocardiogram does not answer every possible question about the heart. Some abnormalities may require exercise testing, longer-term heart-rhythm monitoring, cardiac MRI, or CT angiography to investigate further. The choice depends on what remains unexplained and how strongly the history and examination suggest a cardiac cause.
For example, if a runner describes episodes of sudden palpitations but the heartbeat appears normal during an office visit, a clinician may use a portable ECG monitor to record heart rhythm over a longer period. This is not an imaging test, but it can complement imaging when an electrical problem is being considered. Conversely, when the main concern involves heart structure or coronary anatomy, additional imaging may provide information that a rhythm monitor cannot.
Further testing should be directed at a specific clinical question rather than ordered simply because a person runs long distances. Not every runner with an ache, temporary breathlessness, or an isolated awareness of the heartbeat needs a scan. The initial assessment helps determine whether imaging is likely to change the understanding or management of the problem.
Should a runner stop exercising while waiting for assessment?
Runners should stop exercising when concerning symptoms begin rather than trying to run through them. Fainting during a run, chest discomfort with exertion, or palpitations accompanied by dizziness warrants prompt medical assessment. When fainting during exercise has high-risk features, the American Heart Association and American College of Cardiology recommend withholding competitive sports participation until the necessary evaluation is complete. The decision about returning to training should take the findings and the type of activity into account.
Seek emergency medical help for ongoing chest pressure or pain, collapse, significant breathing difficulty, or chest discomfort accompanied by symptoms such as sweating, nausea, or lightheadedness. The American Heart Association's guidance on heart attack warning signs advises seeking emergency help immediately when symptoms may indicate a heart attack. Do not delay urgent care while arranging an outpatient scan.
How can runners prepare for a cardiac assessment?
Clear information about the episode can help the clinician choose the appropriate tests. Be ready to describe what you were doing when symptoms began, whether they occurred during or after running, how long they lasted, whether they stopped with rest, and whether anything else happened at the same time. Mention any previous episodes, known medical conditions, medicines, supplements, and relevant family history.
Bring details of any previous ECGs, heart scans, or exercise tests if they are available. Avoid strenuous exercise while waiting for assessment when a clinician has advised you to stop, particularly after exercise-related fainting or other concerning symptoms. Ask which activities are appropriate during the evaluation and what findings would be needed before you return to your usual running routine.
Cardiac imaging is most useful when it is selected to answer a clear question about a runner's symptoms. Timely assessment can help clinicians distinguish situations that need further investigation from those in which additional imaging is unlikely to provide useful information.