Shortness of Breath in POTS (Air Hunger): What It Is and What Causes It

Air hunger is the uncomfortable urge to breathe, the sense that a breath is incomplete even when it is deep enough and the oxygen reading is normal, and it has a list of possible causes rather than a single one. I, Dr. Alireza Chizari, DC, DACNB, a board-certified chiropractic neurologist in Calabasas, have found that this particular symptom carries more fear than almost any other. Not being able to get a satisfying breath is frightening in a way that dizziness and fatigue are not, and being told your oxygen saturation is normal does very little to help.

In my experience it also gets misattributed more often than almost any other symptom. If you have been told you are hyperventilating, or that it is anxiety, that may turn out to be part of the answer. It is rarely the whole of it, and it is not where an honest list of causes starts. This guide walks through what air hunger is, what causes it, when it is an emergency, and where dysautonomia and POTS sit on that list.

What Is Air Hunger?

That definition comes from the physiology literature, and it is worth reading slowly. Air hunger is a specific sensation, not a general term for breathing trouble, and the distinction is the reason this symptom is so often described as impossible to explain to anyone. People say they need to sigh, yawn repeatedly, or take a deliberate deep breath that finally catches. What is missing is the sense of completion at the top of the breath.

The review that defines the term is careful about where air hunger sits. It is one quality of breathlessness rather than a synonym for it, and it is distinct from the sensation of breathing work or effort and from the sensation of chest tightness, which arise from different receptors. In most clinical populations studied, air hunger is the predominant form of dyspnea, which is the clinical word for breathlessness, or as the review itself puts it, colloquially, shortness of breath. The same review calls air hunger the most debilitating component of clinical dyspnea. Being handed the word "anxiety" for a sensation described that way in the physiology literature is a poor fit.

The mechanism is a mismatch. Air hunger is thought to reflect the balance between the drive to breathe, set by chemoreceptors and other inputs, and what the lungs actually report moving with each breath. When the drive runs ahead of the movement, the breath feels unfinished. Carbon dioxide is a principal stimulus here, not oxygen alone: stimuli that increase air hunger include hypercapnia (a rise in carbon dioxide), hypoxia (too little oxygen reaching the tissues), exercise and acidosis (too much acid in the blood), while tidal expansion of the lungs, the ordinary filling that happens with each breath in, reduces it.

Those two facts sit awkwardly together for anyone living with this, and it is worth saying which is which. Filling the lungs does reduce air hunger, so the instinct to take one big breath is not a mistake, and the relief it brings is real. What a single breath does not do is change whatever set the drive in the first place, which is why the sensation comes back. That is also why a normal oxygen reading settles less than it seems to. MedlinePlus describes shortness of breath as finding it hard or uncomfortable to take in the oxygen your body needs, with a feeling of not getting enough air. Normal saturation says the lungs are moving oxygen into the blood. It does not say why the urge to breathe is there.

Air hunger vs shortness of breath: what is the difference?

These two get used interchangeably, and the physiology literature is more precise than that. Shortness of breath is the everyday word for dyspnea, and air hunger is one quality of breathlessness rather than a synonym for it. In most clinical populations studied it is the predominant form.

What people mean by air hunger is narrower. The rate may be normal or only slightly raised, the effort is not obviously increased, and the drive is to breathe more deeply rather than more often. People sigh and yawn and describe hitting a ceiling partway into the inhale. The physiology review separates the three deliberately: air hunger, the sensation of breathing work or effort, and chest tightness are three different sensations arising from different receptors, and a person can have one without the others.

In practice the distinction changes what gets investigated. Progressive breathlessness on exertion with a cough, a wheeze, or a falling oxygen reading points toward the lungs, the airways, or the heart. Air hunger with a normal oxygen reading, worse on standing, in someone whose heart rate climbs sharply on standing, points somewhere else entirely.

What Is Air Hunger a Symptom Of?

The honest answer is a list, and a list is not a failure of precision. Air hunger sits on top of breathing difficulty, and breathing difficulty has many causes across several body systems. MedlinePlus sets them out as lung problems (pulmonary embolism, bronchiolitis, COPD, pneumonia, pulmonary hypertension and other lung disease), airway problems (blockage, choking, croup, epiglottitis), heart problems (angina, heart attack, congenital heart disease, heart failure, arrhythmias), and other causes including allergies, altitude, chest-wall compression, dust, emotional distress such as anxiety, hiatal hernia, obesity, panic attacks, anemia, blood disorders and weakness of the breathing muscles.

That list is a set of possibilities to be evaluated, not a menu to diagnose yourself from. What makes it usable when air hunger is the complaint is the pattern around the sensation: when it happens, what position you are in, what else travels with it, and whether it has changed. The same source names several patterns that mean a person should be seen rather than wait, and they are worth reading as a group: chest discomfort, pain or pressure; fever; breathlessness after only slight activity or at rest; breathlessness that wakes you at night or requires sleeping propped up; breathlessness while simply talking; throat tightness or a barking cough; having choked on an object; wheezing; or a significant worsening of your usual breathlessness.

What Diseases Cause Air Hunger?

Several groups of conditions produce this sensation, and more than one can be present at the same time. The order below is not a ranking of likelihood for you personally. It is the order in which the possibilities are usually worth thinking about, starting with the ones most often missed and ending with the one this clinic sees most.

Breathing-pattern disorders

A breathing-pattern disorder is exactly what it sounds like. Dysfunctional breathing, the term used in the literature, is an alteration in the normal biomechanical patterns of breathing that produces intermittent or chronic symptoms, respiratory and non-respiratory. It belongs near the top of any air hunger list, and it often goes unnamed, because there is no gold-standard test for it. Breathing retraining is the main therapeutic approach described.

The absence of a definitive test cuts both ways. It means a breathing-pattern disorder cannot be confirmed the way a chest X-ray confirms a pneumonia, so it should not be assumed simply because other tests came back clear. It also means that when the pattern is visibly there, watching someone breathe upright and lying down tells you more than another round of imaging will.

Anxiety and panic

Anxiety belongs on this list. It belongs on it as one cause among many, never as the default explanation for a symptom nobody has finished investigating. The National Institute of Mental Health describes a panic attack as an episode of intense fear with physical and emotional symptoms, and those symptoms can include difficulty breathing, a pounding or racing heart, chest pain, sweating, trembling, weakness or dizziness, tingling or numb hands, and stomach pain or nausea.

Read that list beside the dysautonomia symptom list further down and the problem becomes obvious. A panic attack and an orthostatic episode share most of their physical vocabulary, and air hunger appears in both accounts. The overlap is close enough that POTS vs panic attacks is a comparison worth working through deliberately rather than settling by how frightening the episode feels, and a person can genuinely have both.

Heart conditions

Cardiac causes sit near the top of the list for a reason: they are the ones where the pattern matters most. The National Heart, Lung, and Blood Institute describes one of the first symptoms of heart failure as feeling short of breath after routine activities like climbing stairs, progressing to noticing it while getting dressed or walking across a room, and notes that some people have shortness of breath while lying flat. MedlinePlus's list adds angina, heart attack, congenital heart disease and arrhythmias.

Air hunger that is worse lying flat is the pattern to take most seriously here, because it runs opposite to the orthostatic pattern described later in this article.

Lung and airway conditions

The lungs and airways are where most people start, and often where testing starts too. Asthma symptoms may include wheezing, coughing especially at night or in the early morning, shortness of breath and chest tightness, and the same source is careful to say that other conditions cause these symptoms too. What is characteristic of asthma is the pattern: symptoms that come and go over time or within the same day.

Air hunger without wheeze, without cough, and without a change in the oxygen reading fits that pattern less well. A quiet chest does not rule asthma out, and the same source says plainly that other conditions produce the same symptoms. It is worth knowing which way the pattern points before an inhaler is tried on suspicion alone.

Anemia, thyroid and sleep

Three whole-body causes come up often enough to name. Iron deficiency anemia is the first: MedlinePlus lists shortness of breath among the symptoms that may appear as the anemia gets worse, alongside fatigue, dizziness, palpitations, feeling lightheaded when you stand up, and problems concentrating. That symptom set overlaps heavily with dysautonomia, which is why blood work belongs early in the sequence rather than late.

Thyroid dysfunction is the second. Hyperthyroidism commonly produces anxiety, difficulty concentrating, fatigue, heat intolerance and a pounding or racing heartbeat. That source does not list breathlessness itself, and the honest point is narrower: an overactive thyroid can reproduce the racing-heart and anxiety picture closely enough to muddle the assessment of someone who also cannot get a full breath.

Sleep-disordered breathing is the third. Sleep apnea is a condition in which breathing stops and restarts many times during sleep, which can prevent the body from getting enough oxygen. If someone has told you that you snore or gasp for air during sleep, that is worth raising with your healthcare provider rather than filing under poor sleep. Air hunger during the day and disrupted breathing at night belong in the same conversation.

Dysautonomia, including POTS

Dysautonomia is where this clinic's patients most often land, and it is listed here rather than first on purpose. The mechanism is worked through further down, and how dysautonomia is evaluated at the clinic is set out in full on its own page. NINDS describes POTS as part of a group of disorders that feature orthostatic intolerance, and its symptom list includes shortness of breath alongside dizziness, fainting, a fast heartbeat, palpitations, exhaustion, headaches, blurred vision, chest pain, fatigue and difficulty concentrating. Scientists still do not know exactly what causes POTS.

Orthostatic intolerance, in the same source's words, describes symptoms that occur when a person stands up and can be relieved by lying down, happening because not enough blood flows back to the heart when the person moves from lying or sitting to standing. That is the sentence that makes breathlessness in POTS make sense, and the rest of this article works through it.

When Is Air Hunger an Emergency?

Most of this article is about the slow version of air hunger, the one that has been going on for months and has already survived a round of normal tests. The fast version is a different matter and needs saying plainly before anything else in here gets used.

Having a dysautonomia diagnosis does not exclude anything else. A symptom that behaves differently from your usual pattern deserves fresh assessment rather than being folded into the existing label, and that is true no matter how long the label has been there.

Can POTS Cause Shortness of Breath?

The positional pattern is the clue that separates air hunger in POTS from the rest of the list, and it is worth checking deliberately rather than from memory. Breathlessness that is worse upright and eases within minutes of lying flat is behaving like POTS. Breathlessness that is worse lying flat, or that has no relationship to position at all, is behaving like something else and needs assessing on its own terms.

POTS itself is defined by the circulatory response to standing. NINDS describes the classic finding as a heart rate that may increase by more than 30 beats per minute, or exceed 120 beats per minute, within 10 minutes of standing, with a threshold of at least 40 beats per minute in adolescents, and notes that the rapid heartbeat usually improves when the person lies down again. Those are diagnostic thresholds, not a severity score, and the window is part of the finding: NINDS describes the change as one that occurs within ten minutes of standing, not at the moment of standing.

What is air hunger in POTS?

Air hunger in POTS is the same sensation described at the top of this article, appearing in a specific pattern: worse on standing, easier lying down, with a normal oxygen reading and a heart rate that climbs. It is the mismatch between how it feels and what the measurements show that sends so many people through respiratory testing before anyone measures a ten-minute orthostatic series.

Why Does POTS Cause Air Hunger and Shortness of Breath?

This is where the anxiety explanation runs into trouble, and where the research gets genuinely interesting.

Reduced cerebral blood flow comes first

A study published in Hypertension examined POTS patients whose chief complaint was breathlessness on standing, against healthy controls, during head-up tilt. The authors compared eleven POTS subjects with breathlessness against ten healthy controls. What they found was a sequence: cerebral blood velocity fell first, and only then did minute ventilation rise and end-tidal carbon dioxide fall. Minute ventilation is the total volume of air moved per minute; end-tidal carbon dioxide is how much is left in the air at the end of a breath out. Sympathetic nerve activity, the output of the body's accelerator system, rose as the exhaled carbon dioxide dropped. The full text is freely available if you want to bring it to an appointment.

The order is what matters. The paper records the fall in cerebral blood flow velocity as preceding the rise in ventilation by "17±6 s", and on that basis the authors hypothesised that reduced perfusion drives the breathing change rather than resulting from it. Their proposed sequence runs: reduced brain blood flow, then activation of the carotid-body chemoreflex (the oxygen and carbon dioxide sensors in the neck triggering a breathing response), then hypocapnic hyperpnea, which means over-breathing with a low carbon dioxide level, and sympathetic activation.

Two honest caveats. The sample was small, and the causal direction is the authors' proposed mechanism rather than a proven one. It also describes a subset of POTS patients, not everyone with the diagnosis. Even with those caveats, it changes the conversation. Anxiety is not irrelevant and I would not claim otherwise. But telling someone with this pattern that they are simply hyperventilating because they are anxious treats the middle of a measured sequence as though it were the beginning.

Blood pooling and reduced return to the heart

On standing, blood shifts downward into the legs and abdomen. NINDS puts the consequence plainly: the symptoms of orthostatic intolerance happen because not enough blood flows back to the heart when a person moves from lying or sitting to standing. The heart rate climbs to compensate for what is returning.

The sensation that follows is often read as a breathing problem, because the chest is where it is felt. The same study proposes something more specific for this subset: exaggerated central hypovolemia early in standing, meaning too little blood in the chest and central circulation, produces the drop in cerebral blood flow velocity and the postural over-breathing that then sustains it. Both halves of that proposal are about being upright, which is why position is the first thing worth tracking rather than the last.

Carbon dioxide, and the loop the study proposes

Once breathing has increased, carbon dioxide falls. The study describes sustained hypocapnia, a low carbon dioxide level, and cerebral ischemia, too little blood reaching the brain, as sustaining each other. That is a loop rather than a straight line: perfusion drops, breathing rises, carbon dioxide falls, perfusion drops further.

It is worth being exact about what that does and does not mean, because air hunger is a topic where internet advice overreaches badly. The physiology review says plainly that filling the lungs reduces air hunger, so a deep breath is not the enemy. What the study proposes is narrower and it is about rate: in this subset of POTS patients, ventilation had already risen, carbon dioxide had already fallen, and the low carbon dioxide is what the authors propose was sustaining the reduced brain blood flow.

If that proposal holds for a given person, the useful target is how fast breathing has increased, not how deep any single breath is. It remains a proposal about a small group, and which of the two is doing the work in your case is a question for an evaluation rather than for an article. Underneath both sits the same relationship named at the top of this article. Carbon dioxide rather than oxygen alone is a principal stimulus for air hunger, which is why CO2 tolerance and the urge to breathe are worth understanding together.

Conditioning, honestly framed

Being told the problem is deconditioning is dismissive, and as an explanation for why this started it is usually wrong. As something that can be worked on, conditioning is real. NINDS says research suggests that cardiovascular rehabilitation with physical activity that slowly builds in intensity can improve tolerance to standing, and in the same breath says it is not recommended for everyone, because some people with POTS also have exercise intolerance.

Both halves of that sentence matter. Graded reconditioning may help. Prescribing it to someone who cannot yet tolerate it, and reading the failure as a lack of effort, does not.

POTS chest tightness, coughing, and breathlessness lying down

Three variations of air hunger come up often enough to address directly. Chest tightness is a different sensation from air hunger rather than a worse version of it; the physiology review says tightness is likely to arise from receptors in the lung, distinct from the drive-versus-movement mismatch that produces air hunger. The two can travel together, which is one of the respiratory and non-respiratory symptom combinations a breathing-pattern disorder can produce. Chest discomfort, pain or pressure of the kind MedlinePlus names as symptoms of angina is not this at all, and belongs in the safety list above.

A dry cough or persistent throat clearing is a symptom to route rather than absorb. A breathing-pattern disorder can produce respiratory as well as non-respiratory symptoms, so a cough alongside this is not automatically evidence of lung disease, and it is not automatically part of the same picture either. What it should not come with is fever, coloured sputum, or a wheeze: MedlinePlus names fever, wheezing and a barking cough among the reasons to be seen, and coughing especially at night or in the early morning, with wheeze, is the asthma pattern NHLBI describes.

Breathlessness lying down deserves particular attention, because it runs against the expected pattern. Air hunger in POTS should ease when you are supine, meaning lying flat on your back. If yours is worse lying flat, or wakes you at night, both NHLBI's heart failure description and MedlinePlus's list of reasons to be seen point the same way: that pattern belongs with your physician rather than being assumed to be dysautonomia.

What Helps Air Hunger?

What helps air hunger depends on what is causing it, which is the unsatisfying but honest headline. Two things are worth saying regardless of cause, and a third applies when the cause is orthostatic.

• Know which lever you are pulling. The physiology review says filling the lungs reduces air hunger, so a full breath can settle the sensation in the moment. Where the Stewart study's proposed loop is involved, the target is the raised rate rather than the depth of any one breath, and that proposal covers a small POTS subset rather than everyone.
• Breathing retraining is the main therapeutic approach the literature describes for dysfunctional breathing. It is not a treatment for an orthostatic problem, and it does not replace finding out what is driving the pattern.
• Where the cause is orthostatic, the circulation is the target. NINDS describes current POTS treatment as focused on managing low blood volume and problems with blood flow, with increased salt intake and hydration to help regulate blood pressure and raise blood volume, and compression garments that go up to the waist to improve blood flow and reduce heart rate on standing. Salt is a conversation to have with your own physician, not a decision to make from an article.

Relaxation and breathing work are worth naming carefully. Relaxation techniques are practices intended to bring about the body's relaxation response, which is characterised by slower breathing, lower blood pressure and a reduced heart rate, and breathing exercises intended to calm the nervous system are one of the types it lists.

That describes what they are for. It does not make them a treatment for the underlying orthostatic problem, a distinction NCCIH makes about relaxation techniques generally, and presenting them as one is how people end up practising breathing exercises for a year while the actual driver goes unmeasured.

How Is Air Hunger Evaluated in Calabasas?

I, Dr. Alireza Chizari, DC, DACNB, am a board-certified chiropractic neurologist and functional neurology specialist at California Brain & Spine Center in Calabasas, and the aim with air hunger here is to establish the sequence rather than to accept the label. A large share of the people I see for air hunger arrive with normal chest imaging, normal lung function testing, and no explanation.

Depending on the history, an assessment may include a full ten-minute orthostatic heart rate and blood pressure series rather than a brief standing check, observation of the breathing pattern in both positions, symptom mapping against posture and provocation, eye movement and gaze stability testing, balance and postural sway measurement, and screening for the cognitive symptoms and the vestibular ones, meaning the inner-ear balance system, that so often travel alongside breathlessness in dysautonomia. Where the findings sit outside our scope, or where anything in the safety list above is present, referral to your primary care provider or a medical specialist is the correct answer and I say so directly.

Where they do fit, care may draw on POTS treatment in Calabasas and dysautonomia care, with attention to the vestibular contribution through vestibular rehabilitation therapies where testing supports it, and to the cognitive symptoms through brain fog treatment in Calabasas. Non-invasive options such as pulsed electromagnetic field therapy may be considered for some presentations, when clinically appropriate after evaluation rather than instead of it. Patients travel to the Calabasas clinic for this from Malibu and across the greater Los Angeles area.

What this often looks like: a year of normal tests

Cases like this are common in our Calabasas clinic, and the pattern is worth describing because so many people assume their version of it is unusual. Someone in her late twenties, working in tech, has been unable to get a full breath for most of a year. Chest X-ray, spirometry, ECG, cardiology review, all normal. A rescue inhaler that did nothing. And more than once, the word anxiety.

She is still working. She has stopped taking the stairs, stopped standing in line, and has begun sitting down in shops in a way she finds humiliating and has not mentioned to anyone.

A ten-minute orthostatic series shows a heart rate rise above the NINDS threshold with no drop in blood pressure. Watching her breathe tells the rest: upright, she shifts into a rapid, shallow, upper-chest pattern within a couple of minutes of standing, and lying down it settles. The pins and needles in her hands that she had never thought to mention fit the same picture, and they are on NIMH's list of physical symptoms too, which is part of why the anxiety reading had stuck.

Care combines circulatory measures with breathing retraining aimed at slowing the rate rather than deepening the breath, plus reconditioning that builds slowly in intensity. Improvement in a case like this is gradual and rarely a straight line, and what any evaluation finds decides the rest. What patients tend to say mattered most is not the improvement itself. It is being shown the sequence, and understanding that the overbreathing may be downstream of something measurable rather than being the thing they were doing wrong.

Your Most Common Questions About Air Hunger

This content is for educational purposes only and is not medical advice. Consult a qualified healthcare provider about your specific situation. Reviewed by Dr. Alireza Chizari, DC, DACNB.

If you have been carrying this symptom for months, the most useful thing I can offer is not reassurance. It is a measurement. Air hunger that has already passed every respiratory test may still have a cause that respiratory testing was never designed to show, and a ten-minute orthostatic series with the breathing pattern watched alongside it is one place that search can go next. California Brain & Spine Center | (818) 649-5300 | 4768 Park Granada, Ste 107, Calabasas, CA 91302, and you can book online at californiabrainspine.janeapp.com.