Can POTS Cause Shortness of Breath?

Shortness of breath is one of the more common and more confusing symptoms of postural orthostatic tachycardia syndrome (POTS), though it rarely shows up on the standard list of hallmark features. Breathlessness drives many POTS patients to pulmonologists, where conventional lung testing often turns up nothing abnormal. The breathing trouble is real, but its origins lie in the autonomic nervous system and circulatory dynamics rather than in the lungs themselves, which is why it tends to puzzle both patients and clinicians.

How Standing Up Triggers Breathing Trouble

POTS is defined by a sustained heart rate increase of at least 30 beats per minute (40 or more in adolescents) within ten minutes of standing, without a significant drop in blood pressure, along with chronic symptoms of orthostatic intolerance.¹ The condition predominantly affects females and peaks between ages 13 and 29. Common symptoms include lightheadedness, palpitations, fatigue, brain fog, and exercise intolerance, but breathlessness belongs on that list too.

The shortness of breath in POTS is tied to what happens inside the chest and brain when you go from lying down to standing. Blood pools in the lower body, reducing the volume that returns to the heart and lungs. That drop in central blood volume also reduces cerebral blood flow. In a study comparing POTS patients whose chief complaint was upright breathlessness with healthy controls during a tilt test, researchers found that cerebral blood flow velocity fell significantly during the initial moments of being upright, and this drop preceded the onset of faster, deeper breathing by about 17 seconds on average.² In other words, the brain senses a supply problem first, and then the breathing pattern changes as the autonomic nervous system scrambles to compensate.

Researchers have proposed that disordered activation of the sympathetic nervous system, driven by reduced blood volume in the chest, may funnel through the carotid body, a small cluster of cells in the neck that monitors blood oxygen and carbon dioxide levels. The idea is that this structure could serve as a common relay point from which many of the varied symptoms of POTS arise, including the sensation of breathlessness that does not fit neatly into a lung-disease model.³ That theory is still being tested, but it offers an explanation for why POTS patients feel short of breath without anything structurally wrong with their airways.

The Hyperventilation Problem

A large proportion of POTS patients hyperventilate when upright.⁴ This is not the dramatic, panicked breathing most people picture when they hear the word. In POTS, it is often subtle, with slightly faster or deeper breaths that the person may not notice consciously. The result, however, is measurable: carbon dioxide (CO2) levels in the blood drop below where they should be, a state called hypocapnia.

Low CO2 causes its own cascade of problems. Blood vessels in the brain constrict when CO2 falls, further reducing cerebral blood flow. The heart rate climbs higher, worsening the tachycardia that already defines POTS.⁴ And paradoxically, even though you are moving more air than normal, the sensation of not getting enough air intensifies. This creates a feedback loop: feeling breathless prompts more breathing, which lowers CO2 further, which makes the heart pound faster and the brain feel more deprived, which feels like you need even more air.

Studies measuring exhaled CO2 during tilt testing have documented this pattern. POTS patients showed progressive decreases in end-tidal CO2 while upright compared with controls, alongside increased minute ventilation, meaning they were breathing more but benefiting less.² Research on postural hypocapnic hyperventilation confirmed this in a group of patients aged 14 to 23, finding that their CO2 levels dropped significantly when tilted upright while their peripheral blood vessels constricted more than in healthy volunteers.⁵ The low CO2 is not a psychological quirk; it is a physiological consequence of how the autonomic system responds to circulatory stress.

This pattern persists during exercise as well, not just standing. In patients with orthostatic intolerance, end-tidal CO2 levels were lower at rest, at anaerobic threshold, and at peak exertion compared to healthy controls.⁶ The hyperventilation is not confined to moments of postural change. It threads through the whole day for some people.

Exercise Intolerance and What Testing Reveals

Exercise intolerance is one of the most debilitating aspects of POTS, and breathlessness during physical activity is a big part of why. Yet formal exercise testing sometimes tells a more nuanced story than patients expect. In a case series of 98 POTS patients who underwent cardiopulmonary exercise testing, peak oxygen uptake was slightly but significantly lower than predicted, and peak work rate was also reduced. However, about 70% of the patients still achieved a normal exercise capacity when measured as a percentage of their predicted peak.⁷

That disconnect can be frustrating. If your numbers look mostly normal on paper but you feel terrible during a flight of stairs, it is easy to feel dismissed. The explanation lies partly in what standard exercise tests measure versus what is going wrong. Standard tests assess peak capacity in a controlled environment. They do not always capture the day-to-day burden of abnormal heart rate responses, hyperventilation, or blood volume problems that accumulate with every upright task.

More specialized testing paints a fuller picture. Using invasive cardiopulmonary exercise testing, which measures pressures inside the heart during exertion, researchers identified two distinct problems contributing to breathlessness in POTS patients: dysfunctional breathing and preload insufficiency. In one study, about 43% of POTS patients demonstrated dysfunctional breathing (either alone or alongside preload insufficiency), and roughly 74% showed preload insufficiency in some form.⁸ Only about one in five patients showed neither abnormality.

Why Low Filling Pressures Matter

Preload insufficiency means that the heart is not receiving enough blood to fill its chambers adequately before each beat. During exercise, a healthy heart relies on increasing venous return to pump harder and deliver more oxygen. When that return is too low, stroke volume does not rise the way it should, and your body cannot supply enough oxygen to working muscles. The result feels like breathlessness and exhaustion that seem disproportionate to the level of effort.

A review of invasive exercise testing in patients with unexplained breathlessness on exertion found that people with low filling pressures had significantly reduced peak cardiac output compared with those who had normal exercise responses. When some of those patients received intravenous saline to temporarily boost their blood volume, about 70% responded with meaningful improvements in cardiac output, stroke volume, and peak oxygen uptake.⁹ That finding highlights how central blood volume plays a direct role in how breathless you feel during exertion.

For POTS patients specifically, saline infusions have shown broader symptom benefits. In a group of patients who had not responded adequately to medications, intermittent IV saline led to significant improvements in orthostatic symptom scores and quality-of-life measures.¹⁰ While IV saline is not practical for everyday use, the finding reinforces the idea that low circulating volume is a key driver of symptoms, including breathlessness. Increasing oral fluid and salt intake follows the same logic on a smaller scale, which is why those recommendations are so consistently emphasized in POTS management.

When Hypermobility Compounds the Problem

A significant subset of POTS patients also have hypermobile Ehlers-Danlos syndrome (hEDS) or generalized hypermobility spectrum disorder, and that overlap adds an extra layer to the breathing picture. In individuals with hEDS, the estimated prevalence of breathlessness is around 50%. More strikingly, respiratory muscle weakness occurs in over 75% of people with hEDS, which can produce a restrictive pattern of breathing where the lungs cannot fully expand.¹¹

So a person with both POTS and hEDS may be dealing with autonomic-driven hyperventilation on top of weak respiratory muscles that limit how effectively they can move air. These are mechanistically separate problems that compound each other. A chest wall that gives too easily because of connective tissue laxity means the usual signals your brain uses to calibrate breathing are disrupted, while the autonomic dysfunction is simultaneously driving your breathing rate higher than it needs to be. Each condition can cause breathlessness on its own; together, they are worse than the sum of their parts.

If you have been diagnosed with POTS and your breathlessness seems worse than what other POTS patients describe, joint hypermobility is worth exploring with your physician. A targeted assessment of respiratory muscle strength can identify whether that additional factor is at play.

Why Breathing Complaints Get Bounced Between Specialists

One of the more frustrating aspects of POTS-related breathlessness is how long it takes to get a satisfying explanation. Standard pulmonary function tests typically come back normal because the lungs themselves are healthy. Chest X-rays look fine. Asthma treatments do not help. Patients end up being referred to pulmonologists for breathlessness, cardiologists for chest pain or palpitations, neurologists for “spells,” and gastroenterologists for nausea, sometimes circulating among all four before anyone connects the dots.³

The underlying issue is that the breathlessness in POTS does not fit the frameworks these specialists typically work with. Pulmonologists look for lung disease. Cardiologists look for heart failure or valve problems. The concept of dyspnea driven by autonomic misfiring and low blood volume falls between disciplines. Researchers have pointed out that the traditional model of breathlessness, where the brain’s breathing commands and the mechanical response of the lungs are mismatched, does not fully capture what happens in POTS. The breathing sensation can arise from autonomic disruption alone, without any mechanical problem in the chest.³

If you are experiencing unexplained breathlessness that worsens when you stand or during light exertion, and it comes alongside other POTS-like symptoms such as rapid heart rate, dizziness, or fatigue, raising the possibility of POTS with your doctor can save months of specialist visits. A tilt-table test or even a simple active standing test with heart rate monitoring can point toward the diagnosis.

Dysfunctional Breathing and What Can Help

Breathlessness in POTS is sometimes categorized as dysfunctional breathing or hyperventilation syndrome, a label that anecdotally applies to many POTS patients who report breathing trouble.¹² This is not the same as saying the problem is imaginary. Dysfunctional breathing means the pattern of breathing has shifted in a way that produces symptoms, often without the person being aware of it. Breathing too quickly, breathing too deeply, or using the upper chest instead of the diaphragm can all contribute.

Physiotherapy approaches that retrain breathing patterns show promise. Techniques include slow diaphragmatic breathing, where you consciously slow your breath rate and focus on expanding the belly rather than the upper chest. The goal is to normalize CO2 levels, reduce the sympathetic overdrive that worsens tachycardia, and break the feedback loop between breathlessness and hyperventilation. These approaches do not cure POTS, but for the subset of patients where dysfunctional breathing is a major contributor, they can meaningfully reduce how often and how severely breathlessness strikes.

General POTS management strategies also help the breathing component indirectly. Adequate hydration and salt intake expand blood volume, which addresses the preload insufficiency that drives both the heart rate spikes and the reduced cerebral blood flow. Graduated exercise programs, particularly those that start in a reclined position like rowing or swimming, can improve cardiovascular conditioning over time and reduce the autonomic overreaction to standing. Compression garments push blood back toward the core, countering the pooling that sets the whole chain of events in motion.

The Emotional and Psychological Layer

Breathlessness is an inherently anxiety-provoking sensation, and POTS patients frequently report that their breathing difficulties get worse during stressful moments. This is not a sign that the problem is “all in your head.” Stress activates the sympathetic nervous system, the same system already running too hot in POTS, which amplifies every symptom including the breathing disruption. Research has found that POTS patients with higher levels of past trauma and post-traumatic stress report significantly worse overall symptom severity, with those meeting criteria for PTSD scoring much higher on symptom scales than those who did not.¹³

The practical implication is that psychological wellbeing and nervous-system regulation are not separate from POTS management. They are part of it. Approaches that calm the autonomic nervous system, whether cognitive behavioral therapy, mindfulness-based techniques, or trauma-informed care, may reduce the amplification of symptoms including breathlessness. This is not about dismissing the physical reality of POTS. It is about recognizing that a nervous system under multiple forms of stress, whether from blood volume problems or psychological burden, will produce worse symptoms across the board.

When Breathlessness in POTS Needs More Workup

Not every episode of breathlessness in a POTS patient is from POTS. Conditions that can produce similar symptoms include asthma, anemia, pulmonary embolism, heart valve disease, and deconditioning from prolonged inactivity. If your breathing suddenly changes in character, gets worse lying down rather than standing, comes with new chest pain or leg swelling, or is accompanied by low oxygen readings on a pulse oximeter, those are flags that something else may be going on. POTS-related breathlessness does not typically cause low oxygen saturation. If your oxygen is consistently reading below 95%, that warrants investigation beyond POTS.

It is also worth knowing that POTS can coexist with asthma or other lung conditions. Having POTS does not protect you from developing a separate respiratory problem. The key distinction is positional: if breathlessness reliably worsens when you stand and improves when you sit or lie down, the autonomic component is likely playing a major role. If it is constant regardless of position, something else deserves a closer look.