Postural Orthostatic Tachycardia Syndrome Symptoms: A Doctor’s Complete Guide to POTS

Postural orthostatic tachycardia syndrome symptoms commonly include a racing or pounding heart, dizziness, lightheadedness, shakiness, blurred vision, weakness, breathlessness, nausea, fatigue and difficulty thinking when standing or sitting upright. Symptoms usually improve after lying down.

The pattern of symptoms matters as much as the individual symptoms. Postural orthostatic tachycardia syndrome—commonly abbreviated to POTS or PoTS—is a form of orthostatic intolerance. This means the body has difficulty adjusting its circulation when a person moves into an upright position.

However, symptoms alone cannot confirm POTS. Diagnosis also requires a characteristic, sustained increase in heart rate and the exclusion of other possible explanations, such as dehydration, anaemia, thyroid disease, medication side effects and abnormal heart rhythms.

This guide explains what POTS feels like, the most common symptoms, what can trigger a flare, how the condition is diagnosed and when symptoms require urgent medical attention.

Please note: This guide provides general medical information and should not be used as a substitute for an individual diagnosis. Symptoms such as chest pain, breathlessness, fainting and a fast heartbeat can have causes unrelated to POTS.

POTS Symptoms at a Glance

What Does POTS Feel Like?

People with POTS often describe feeling relatively well while lying down but becoming unwell after standing, walking, showering, waiting in a queue or sitting upright for a prolonged period.

The heart may suddenly begin to pound, vision may dim and the legs may feel heavy, weak or unsteady. Some people feel as though they are about to faint, while others mainly experience overwhelming fatigue, nausea or cognitive difficulties.

POTS symptoms can vary considerably between individuals. A person does not need to experience every symptom, and POTS does not always cause fainting.

Presyncope—the sensation that you may be about to faint—is generally more common than complete loss of consciousness.

The defining clinical clue is orthostatic worsening: symptoms appear or become more intense while upright and improve, at least partly, after lying down.

The Most Common Postural Orthostatic Tachycardia Syndrome Symptoms

1. A Fast or Pounding Heartbeat After Standing

A noticeable increase in heart rate is central to POTS. It may feel like racing, pounding, fluttering or forceful beats in the chest or neck.

Some people notice the change immediately after standing. In others, it develops gradually over several minutes.

A fast heart rate is not automatically POTS. Fever, pain, anxiety, dehydration, blood loss, anaemia, an overactive thyroid, certain medicines and abnormal heart rhythms can also cause tachycardia.

2. Dizziness and Lightheadedness

Dizziness may begin after getting out of bed, rising from a chair or standing still. It can also develop after prolonged upright sitting.

A person may feel unsteady, detached or as though the room is fading around them.

True spinning vertigo is less characteristic of POTS and may suggest a problem involving the inner ear or balance system.

3. Near-Fainting or Fainting

Near-fainting can cause:

• Greying or darkening vision
• Tunnel vision
• Muffled hearing
• Sweating
• Nausea
• Sudden weakness
• A feeling that collapse is imminent

Fainting can occur, particularly when POTS overlaps with vasovagal syncope. However, many people with POTS never completely lose consciousness.

4. Severe Fatigue

POTS fatigue can be disproportionate to the amount of activity performed.

Standing long enough to prepare food or taking a shower may leave someone needing to sit or lie down. The fatigue can continue even after the heart rate has returned to normal.

Fatigue can also overlap with post-viral illness, sleep disorders, anaemia, thyroid disease and other medical conditions. These possibilities may need to be investigated.

5. Brain Fog

“Brain fog” describes difficulty:

• Concentrating
• Finding the right words
• Remembering information
• Following conversations
• Processing thoughts
• Multitasking
• Thinking at a normal speed

Brain fog is not a formal medical diagnosis, but it is a common and sometimes disabling POTS symptom.

It may be particularly noticeable while upright, after physical exertion, during heat exposure or during a POTS flare.

6. Exercise Intolerance

Exercise may cause an unusually rapid heart rate, dizziness, weakness, nausea or a prolonged worsening of symptoms.

Some people find upright exercise—such as running or using a treadmill—particularly difficult.

Deconditioning can develop when symptoms restrict physical activity, but it should not automatically be assumed to be the original cause of POTS.

Exercise and rehabilitation plans must be personalised. This is especially important for people who experience post-exertional symptom exacerbation, where symptoms become significantly worse after physical or mental activity.

7. Headaches and Migraine

Headaches, head-pressure sensations and migraines are frequently reported by people with POTS.

A new, sudden or extremely severe headache requires urgent medical assessment. The same applies to a headache accompanied by weakness, confusion, difficulty speaking or loss of vision.

These symptoms should not simply be attributed to POTS.

8. Nausea and Digestive Symptoms

POTS can be associated with several digestive symptoms, including:

• Nausea
• Abdominal discomfort
• Bloating
• Feeling full unusually quickly
• Constipation
• Diarrhoea
• Reduced appetite

Digestion redirects blood towards the abdomen. This may explain why some people with POTS feel worse after eating, particularly after a large meal.

Persistent vomiting, unexplained weight loss, blood in the stool, black stools or severe abdominal pain require separate medical assessment.

9. Shaking, Sweating and Temperature Intolerance

Some people experience:

• Trembling
• Internal shakiness
• Excessive sweating
• Reduced sweating
• Hot flushes
• Chills
• Cold hands and feet
• Marked heat intolerance

Hot weather, fever, hot baths and hot showers can widen the blood vessels and aggravate orthostatic symptoms.

10. Breathlessness

A person with POTS may feel breathless or unable to take a satisfying breath during an episode.

However, breathlessness has many possible causes, including asthma, infection, anaemia, blood clots, heart disease and lung disease.

New, severe or unexplained breathlessness should not automatically be attributed to POTS.

11. Chest Pain or Chest Discomfort

Chest tightness, pressure or discomfort can occur alongside a rapid heart rate.

Because chest pain can also indicate a heart, lung or circulatory emergency, it is important to take new, severe or persistent chest pain seriously.

Chest pain occurring during exercise or accompanied by fainting, sweating, severe breathlessness or pain spreading to the arm, jaw or back requires urgent medical help.

12. Purple or Blotchy Feet and Legs

Blood pooling in the lower body can cause reddish-purple discolouration of the feet and legs. This is sometimes called dependent acrocyanosis or informally referred to as “POTS feet.”

The discolouration generally appears while standing and improves after sitting or lying down with the legs elevated.

A single swollen, painful or unusually warm leg is not a typical POTS symptom. It requires urgent assessment for a possible blood clot.

13. Weak or Heavy Legs

Blood pooling and reduced tolerance of upright posture can cause the legs to feel:

• Heavy
• Weak
• Achy
• Unsteady
• Difficult to move

These sensations commonly become worse after prolonged standing or walking.

Sudden weakness affecting one side of the body is not a typical POTS symptom and requires emergency medical assessment.

14. Sleep Disturbance

People with POTS may experience:

• Difficulty falling asleep
• Frequent waking
• Poor-quality sleep
• Feeling unrefreshed after sleeping
• Daytime sleepiness
• A racing heart at night

Sleep apnoea, restless legs syndrome, medication effects and other sleep disorders can produce similar symptoms and should be considered where appropriate.

What Triggers a POTS Flare?

POTS symptoms may fluctuate from hour to hour or day to day. Some people experience periods when their symptoms are relatively manageable, followed by significant flares.

Common POTS triggers include:

• Standing still
• Sitting upright for a long time
• Getting out of bed quickly
• Hot weather
• Hot baths or showers
• Dehydration
• Fever or acute illness
• Large meals
• Meals high in refined carbohydrates
• Alcohol
• Physical overexertion
• Inadequate sleep
• Emotional stress
• Pain
• Menstruation
• Hormonal changes
• Prolonged bed rest
• Medicines that increase heart rate
• Medicines that reduce blood pressure
• Medicines that promote fluid loss

Triggers differ between individuals. Keeping a symptom, activity and heart-rate diary may help identify patterns, but it should support rather than replace a proper clinical assessment.

POTS Diagnostic Criteria

Doctors do not diagnose POTS from symptoms alone.

Current consensus criteria generally require all the following features:

1. A sustained heart-rate increase of at least 30 beats per minute in adults within 10 minutes of standing or head-up tilt.
2. For people aged 12 to 19 years, a sustained heart-rate increase of at least 40 beats per minute within 10 minutes.
3. No sustained orthostatic hypotension, which is defined as a blood-pressure fall of at least 20 mmHg systolic or 10 mmHg diastolic.
4. Frequent symptoms of orthostatic intolerance that become worse while upright and improve after returning to a lying position.
5. Symptoms lasting for at least three months.
6. No other condition that adequately explains the sinus tachycardia.

The heart-rate increase should generally be present in more than one measurement taken at least one minute apart.

A person does not have to reach an absolute heart rate of 120 beats per minute to have POTS. Equally, a brief heart-rate spike immediately after standing is not sufficient to establish the diagnosis.

Heart-rate responses can vary depending on:

• Hydration
• Time of day
• Recent meals
• Medication
• Caffeine
• Hormonal changes
• Sleep
• Acute illness

If a person has a strongly suggestive history but their initial assessment is normal, a clinician may repeat the standing measurements. Testing in the morning can sometimes be more revealing because orthostatic tachycardia may be more pronounced earlier in the day.

Can You Test for POTS at Home?

A home standing test may provide useful information, but it cannot safely confirm or exclude POTS.

Consumer smartwatches and fitness trackers may also produce inaccurate readings, particularly during movement.

If a healthcare professional says it is safe to collect readings, they may ask you to:

1. Lie down quietly for five to ten minutes.
2. Record your heart rate and blood pressure while lying down.
3. Stand carefully.
4. Record your heart rate and blood pressure at regular intervals for up to 10 minutes.
5. Note any symptoms that develop.

Stop the test immediately and lie down if you feel faint or unsafe.

Do not perform a standing test alone if you:

• Have previously fainted
• Are at risk of falling
• Are pregnant
• Have significant heart disease
• Have recently experienced severe chest pain
• Feel acutely unwell

Share the readings, symptoms, time of day, recent food and fluid intake, and current medicines with a healthcare professional.

Do not diagnose yourself from the numbers alone.

How Doctors Test for POTS

An assessment for possible POTS commonly includes:

• A detailed history of symptoms
• Questions about triggers and symptom duration
• An assessment of how symptoms affect daily life
• Lying and standing heart-rate measurements
• Lying and standing blood-pressure measurements
• A physical examination
• A 12-lead electrocardiogram
• A review of medicines, supplements and stimulants
• Blood tests to investigate alternative causes

Blood tests may include:

• Full blood count
• Ferritin or iron studies
• Electrolytes
• Kidney function
• Thyroid function
• Blood glucose
• Morning cortisol

A tilt-table test may be used when the diagnosis remains uncertain or more detailed monitoring is required.

Depending on the symptoms, a clinician may also arrange:

• Ambulatory heart monitoring
• An echocardiogram
• Additional autonomic testing
• Exercise testing
• Neurological assessment
• Further blood tests

There is no single blood test, scan or symptom questionnaire that can prove someone has POTS.

Conditions That Can Mimic POTS Symptoms

Many common and treatable conditions can cause dizziness, fatigue and tachycardia.

Important alternative explanations include:

• Dehydration
• Recent blood loss
• Iron deficiency
• Anaemia
• Fever
• Infection
• Significant pain
• Hyperthyroidism
• Adrenal insufficiency
• Pregnancy
• Medication side effects
• Stimulant use
• Prolonged bed rest
• Severe deconditioning
• Orthostatic hypotension
• Vasovagal syncope
• Inappropriate sinus tachycardia
• Supraventricular tachycardia
• Other cardiac arrhythmias
• Heart disease
• Lung disease
• Panic attacks
• Severe anxiety

Anxiety can cause genuine physical symptoms and can coexist with POTS. However, positional tachycardia should not be dismissed as anxiety without an appropriate history and clinical assessment.

Conversely, experiencing several symptoms associated with POTS does not rule out anxiety or another medical condition.

POTS Symptoms in Teenagers

POTS often begins during adolescence, sometimes following an infection, operation or period of reduced physical activity.

Teenagers may report:

• Dizziness during school assemblies
• Difficulty standing in queues
• Fatigue
• Headaches
• Nausea
• Brain fog
• Poor concentration
• Poor exercise tolerance
• Difficulty standing in the shower
• Needing to sit or lie down frequently
• Problems attending school

The diagnostic heart-rate threshold for people aged 12 to 19 is higher than the adult threshold. Their heart rate must increase by at least 40 beats per minute within 10 minutes of becoming upright.

Normal growth, hydration, eating habits, sleep, iron deficiency, menstrual blood loss and medication use should also be considered.

New symptoms affecting school attendance, mobility or ordinary activities warrant medical assessment.

POTS, Infections and Long COVID

POTS can begin after a viral infection. A POTS-like pattern has also been recognised in some people with long COVID.

Symptoms may include:

• Dizziness
• Palpitations
• Exercise intolerance
• Brain fog
• Fatigue
• Breathlessness
• Headaches
• Nausea

However, fatigue, breathlessness, palpitations and cognitive difficulties following an infection have numerous possible causes.

A healthcare professional should assess the complete clinical picture rather than assuming every case of post-viral illness is POTS.

Are There Different Types of POTS?

Terms such as neuropathic POTS, hyperadrenergic POTS and hypovolaemic POTS describe possible contributing mechanisms.

These categories can overlap and cannot be reliably diagnosed from symptoms alone.

Neuropathic POTS

Neuropathic features may involve problems with the nerves controlling blood-vessel constriction. This can allow excessive blood to pool in the legs and lower body.

Hyperadrenergic POTS

Possible symptoms include:

• Prominent trembling
• Sweating
• Palpitations
• Feelings of agitation
• Headaches
• An increase in blood pressure while upright

These symptoms can resemble anxiety, but they may reflect an excessive sympathetic nervous system response.

Hypovolaemic POTS

Hypovolaemia means that the volume of circulating blood is lower than expected. This may contribute to tachycardia, weakness and reduced tolerance of standing.

Secondary POTS

Secondary POTS describes a POTS pattern that occurs alongside another medical condition.

Treatment should be based on an individual clinical assessment rather than an online POTS subtype test.

When Should You Seek Urgent Medical Help?

Call your local emergency services or seek urgent medical assessment if you experience:

• New, severe or persistent chest pain
• Severe difficulty breathing
• Blue or grey lips
• A low oxygen level
• Fainting during exercise
• Fainting while lying down
• A very fast heartbeat that does not settle
• A new or markedly irregular heartbeat
• Fainting with a significant injury
• Prolonged confusion after fainting
• Seizure-like activity
• New weakness affecting one side of the body
• Facial drooping
• Difficulty speaking
• Sudden loss of vision
• Coughing up blood
• A single swollen and painful leg
• Heavy bleeding
• Black stools
• Vomiting blood
• Inability to keep fluids down
• Minimal urine output
• Marked drowsiness or confusion

Use the emergency number for your country. Do not drive yourself if you feel faint or seriously unwell.

Arrange a routine medical appointment if recurrent dizziness, palpitations, fatigue or near-fainting is affecting your daily life, even if the symptoms improve when you lie down.

How POTS Symptoms Are Managed

POTS treatment is individualised. It may combine practical measures with treatment of contributing or associated medical conditions.

A healthcare professional may recommend:

• Maintaining adequate fluid intake
• Increasing dietary salt when medically appropriate
• Wearing waist-high compression garments
• Avoiding or modifying known triggers
• Eating smaller meals
• Using physical counter-pressure manoeuvres
• Following an individualised exercise or rehabilitation programme
• Taking medication when non-drug measures are insufficient

Increasing salt or fluid intake is not safe for everyone. It may be unsuitable for some people with:

• Heart disease
• Kidney disease
• High blood pressure
• Certain endocrine conditions

Medication choices depend on heart rate, blood pressure, pregnancy potential, other illnesses and the person’s most troublesome symptoms.

Do not begin, stop or change prescribed treatment without medical advice.

If dizziness begins, lie down and raise your legs if possible.

If you cannot lie down safely, the following manoeuvres may temporarily support blood flow while you find somewhere safe to sit:

• Cross your legs tightly
• Clench your fists
• Tense your leg muscles
• Tighten your abdominal muscles
• Clench your buttock muscles
• Rock up and down on your toes

How to Describe POTS Symptoms to Your Doctor

Before your appointment, make a note of:

• What the symptoms feel like
• When the symptoms begin
• Whether standing triggers them
• Whether prolonged sitting triggers them
• Whether eating, heat or exercise makes them worse
• How quickly lying down provides relief
• Any fainting, falls or injuries
• Heart-rate and blood-pressure readings, if safely obtained
• Your usual fluid intake
• Recent illnesses
• Menstrual bleeding or other possible blood loss
• All medicines and supplements
• Caffeine, nicotine or other stimulant use
• How symptoms affect work, education, walking, showering, cooking and sleep

The pattern of symptoms is often more diagnostically helpful than a long, unstructured list.

Frequently Asked Questions

What are the first signs of POTS?

Early signs of POTS may include a racing heart, lightheadedness, shakiness, weakness, blurred vision or nausea after standing.

Some people initially notice unexplained fatigue, difficulty showering or an unusual need to sit or lie down.

What is the hallmark symptom of POTS?

The hallmark is not one symptom but a particular pattern: symptoms of orthostatic intolerance accompanied by a sustained and excessive increase in heart rate after becoming upright, without significant orthostatic hypotension.

Does POTS cause fainting?

POTS can cause fainting, but fainting is not required for diagnosis. Near-fainting, dizziness and visual dimming are generally more common.

Can POTS cause symptoms while sitting?

Yes. Prolonged upright sitting can provoke symptoms in some people, although standing is usually more challenging. Lying down normally provides at least partial relief.

Can POTS cause anxiety-like symptoms?

Palpitations, trembling, sweating and breathlessness can resemble anxiety symptoms.

POTS and anxiety can also occur together. The consistent relationship to upright posture and objectively measured heart-rate changes can help clinicians distinguish between the conditions.

Is blood pressure low in POTS?

Blood pressure may be low, normal or sometimes increase in people with POTS.

A sustained blood-pressure fall that meets the definition of orthostatic hypotension suggests a different or additional diagnosis.

Can a smartwatch diagnose POTS?

No. A smartwatch may help document heart-rate trends, but it cannot assess all the diagnostic criteria, reliably identify abnormal rhythms or rule out other causes.

Smartwatch readings should be interpreted by a healthcare professional.

Can you have POTS with a normal resting heart rate?

Yes. Many people with POTS have a normal heart rate while lying down. The important finding is the excessive and sustained increase in heart rate after becoming upright.

Do POTS symptoms happen every day?

Symptoms may occur daily, intermittently or in flares. Their severity can change depending on hydration, temperature, physical activity, sleep, illness, meals and hormonal changes.

Does POTS always start suddenly?

No. POTS may appear suddenly after an infection, operation, pregnancy or other event. In other people, symptoms develop gradually without an obvious trigger.

Do POTS symptoms go away?

The course varies between individuals.

Symptoms can improve substantially with time and personalised management. Some people experience periods of remission and relapse, while others have persistent symptoms.

The outlook may depend on age, underlying triggers and associated medical conditions.

The Key Takeaway

Postural orthostatic tachycardia syndrome symptoms are often multisystem, but they share a recognisable pattern: they become worse when a person is upright and improve after lying down.

A racing heart, dizziness, near-fainting, fatigue, brain fog, nausea and exercise intolerance are among the most frequently reported symptoms. However, none of these symptoms is specific to POTS.

Diagnosis requires carefully measured heart rate and blood pressure, persistent orthostatic symptoms and the exclusion of alternative causes.

If your symptoms are recurrent or interfere with normal activities, arrange a medical assessment rather than relying on a smartwatch, home standing test or online symptom checker.

Medical References

1. Raj SR, Fedorowski A, Sheldon RS. Diagnosis and management of postural orthostatic tachycardia syndrome. CMAJ. 2022;194(10)–E385.
2. Vernino S, Bourne KM, Stiles LE, et al. Postural orthostatic tachycardia syndrome: State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting. Autonomic Neuroscience. 2021;235:102828.
3. Sheldon RS, Grubb BP II, Olshansky B, et al. 2015 Heart Rhythm Society Expert Consensus Statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia and vasovagal syncope. Heart Rhythm. 2015;12(6)–e63.
4. National Heart, Lung, and Blood Institute. Postural Orthostatic Tachycardia Syndrome: State of the Science, Clinical Care and Research.
5. NHS. Postural tachycardia syndrome (PoTS).
6. Johns Hopkins Medicine. Postural Orthostatic Tachycardia Syndrome (POTS).