Are There Exercise Restrictions for an ASD or PFO?

If you have an unclosed atrial septal defect (ASD) or patent foramen ovale (PFO), the need for exercise restrictions depends primarily on the size of the hole, how much blood flows through it, and whether it has caused secondary changes to your heart or lungs. For the vast majority of people with a PFO or a small, asymptomatic ASD, there are no restrictions on playing sports, lifting weights, or general physical activity. However, if you have a larger ASD that has caused right-heart strain, or if you participate in specialized activities like scuba diving, certain limitations and precautions will apply.

Small ASDs and PFOs

If you have a PFO or a small ASD that does not cause symptoms, you are generally encouraged to lead a fully active life ^[1][2]. Cardiovascular exercise is healthy, and there is no evidence suggesting you need to restrict routine sports or physical activity ^[3][4].

Many patients wonder about weightlifting because it often involves bearing down or holding your breath (the Valsalva maneuver). This action temporarily increases pressure in the chest and can push small amounts of blood from the right side of the heart to the left side ^[5][6].

You might wonder if a hard gym session could cause a blood clot to cross the hole and trigger a stroke. For individuals without a history of blood clots or stroke, the risk of a first-time stroke triggered by exercise is incredibly low, and weightlifting is considered safe ^[1][6]. However, there are two important exceptions:

• Prior Stroke or TIA: If you have a history of paradoxical embolism (a stroke or TIA caused by a clot crossing the hole), you should explicitly discuss weightlifting limits with your cardiologist before returning to the gym.
• Blood Thinners: If you are taking blood thinners to prevent clots, you should avoid high-impact contact sports due to the risk of internal bleeding.

Practical gym tip: Rather than worrying about a specific arbitrary weight limit (like 50 pounds), focus on your breathing. Avoid holding your breath to brace your core during heavy lifts. Instead, practice continuous breathing—exhale on the exertion phase of the lift to avoid creating a massive pressure buildup in your chest.

Large ASDs, Heart Strain, and Pulmonary Hypertension

If an ASD is large, a significant amount of blood shunts into the right side of the heart, forcing it to work harder. Over time, this can lead to right heart volume overload (enlargement of the right-sided heart chambers) and pulmonary hypertension (high blood pressure in the arteries of the lungs) ^[7][8].

If your ASD has caused these complications, your doctor will likely recommend modifying your activity:

• Avoid heavy lifting and competitive sports: Extreme physical exertion places excess demand on an already strained right heart, which could trigger dangerous arrhythmias (irregular heartbeats) or worsen heart failure ^[9][10].
• High-Altitude Activities: If you have pulmonary hypertension, lower oxygen environments (like high-altitude skiing, hiking, or mountaineering) can acutely worsen blood pressure in your lungs. Consult your doctor before traveling to high altitudes.
• Focus on symptom-limited activity: If you develop severe pulmonary hypertension or Eisenmenger syndrome (a condition where blood flow through the heart reverses and oxygen levels drop), your exercise capacity will naturally be severely impaired ^[11][12]. In these cases, physical activity must be kept at a low intensity to avoid life-threatening complications ^[11].

Scuba Diving Considerations

The most universally recognized physical restriction for both PFOs and ASDs involves scuba diving. When a diver breathes compressed air underwater and then ascends, tiny nitrogen bubbles can form in the bloodstream. Normally, the lungs filter these bubbles out safely. However, if you have a hole between your atria, these nitrogen bubbles can bypass the lungs, cross directly into the arterial bloodstream (a process called paradoxical embolization), and travel to the brain or spinal cord ^[13][14].

This significantly increases your risk of decompression sickness (the “bends”). For this reason:

• Divers with a known PFO or ASD are often advised to adopt very conservative dive profiles (e.g., shallower depths, avoiding decompression stops) to minimize bubble formation ^[15].
• If you have already experienced decompression sickness, diving medicine experts usually recommend stopping diving or undergoing a procedure to close the hole before returning to the water ^[16]. Even after closure, a conservative approach is usually recommended ^[15].

Always discuss your specific exercise goals and any new physical activities with your care team so they can tailor advice to your unique heart anatomy.