Have you ever stood up and suddenly felt your heart pounding?
Perhaps you become dizzy, your vision blurs, your legs feel strangely heavy, or you have to sit back down almost immediately.
Most people can stand without giving it a second thought.
For some people, standing feels like exercise.
If that sounds familiar, you may have heard of POTS or orthostatic intolerance.
These conditions have become increasingly recognised since the COVID-19 pandemic, but they are not new. For years, many people were told their symptoms were caused by anxiety, stress or simply being unfit. We now know that, for many, the problem lies somewhere very different: the autonomic nervous system.
Most people never think about standing up. Their heart adjusts automatically. Blood continues flowing to the brain, and life carries on without a second thought.For people living with Postural Orthostatic Tachycardia Syndrome (POTS) or other forms of orthostatic intolerance, something very different happens.
Simply standing can make the heart race, vision blur, legs feel heavy, breathing become difficult, and thinking suddenly much harder.For years, many people were told these symptoms were caused by anxiety or stress. Today, we know POTS is a recognised disorder of the autonomic nervous system that affects how the body regulates heart rate and blood flow. It has also become increasingly recognised after viral infections, including COVID-19.
Standing Up Shouldn’t Be This Hard
Every time you stand, gravity pulls blood towards your legs and abdomen. Your body normally fixes this before you even notice it.Blood vessels tighten.Your heart makes small adjustments.Blood keeps flowing to your brain. You stay upright without thinking about it.
People with POTS still experience gravity.The difference is that their bodies struggle to compensate.More blood stays in the lower part of the body, less returns to the heart, and the autonomic nervous system works much harder to keep enough blood reaching the brain.
The result can be a racing heart, dizziness, blurred vision, nausea, fatigue and brain fog all triggered simply by standing
So, What Is POTS?
POTS stands for Postural Orthostatic Tachycardia Syndrome.It is one form of dysautonomia, a group of conditions affecting the autonomic nervous system the part of your nervous system responsible for all the things you never have to think about.It helps control your heart rate, blood pressure, breathing, digestion, body temperature and many other automatic functions.When this system stops regulating blood flow properly, even everyday activities like standing in a queue, having a shower or cooking dinner can become unexpectedly exhausting.
Why Does Your Heart Race?
Many people assume the heart is the problem.In most cases, it isn’t.Your heart is often responding exactly as it has been told to.Because less blood is returning to it when you stand, it beats faster in an attempt to keep enough oxygen reaching your brain.The racing heartbeat is often a sign that your body is trying to compensate for poor circulation, not necessarily that your heart itself is damaged.
That’s why many people with POTS have completely normal ECGs, echocardiograms and routine heart tests.The problem is not usually the heart.It’s how the body controls it.
What Does POTS Feel Like?
POTS can look different from one person to another, but many people describe a surprisingly similar pattern.You stand up.Your heart suddenly starts racing.You feel light-headed, shaky or unsteady.Your thoughts become harder to organise, almost as if someone has turned the brightness down inside your brain.For some people, it feels as though they might faint. Others simply feel exhausted after standing for only a few minutes.
Common symptoms include:
- A racing or pounding heartbeat when standing
- Dizziness or feeling faint
- Brain fog and difficulty concentrating
- Fatigue that worsens when upright
- Shortness of breath
- Nausea or digestive problems
- Cold hands and feet
- Heat intolerance
- Trembling or shakiness
- Feeling much better after lying down
Not everyone experiences every symptom, and symptoms often fluctuate from day to day.
Why Is Standing Still Worse Than Walking?
This is one of the questions people ask most.Surely walking should be harder than standing still?
Surprisingly, for many people with POTS, the opposite is true.When you walk, the muscles in your legs squeeze with every step. That helps pump blood back towards your heart.When you stand still, that muscle pump switches off.Blood has more opportunity to collect in the legs, meaning your heart and autonomic nervous system have to work much harder to keep enough blood reaching your brain.
That’s why waiting in a supermarket queue can sometimes feel harder than walking around the shop.
Why Do I Feel Better When I Lie Down?
Many people notice that lying flat brings almost immediate relief.That’s because gravity is no longer pulling blood towards your legs.Blood returns more easily to your heart and brain, meaning your body no longer has to compensate so aggressively.The racing heart slows.Your head feels clearer.Standing becomes easier again at least until you get back upFor many people with POTS, this rapid improvement after lying down is one of the biggest clues that the autonomic nervous system is involved.
Why Does POTS Happen?
There isn’t one single cause.
POTS is better thought of as a syndrome rather than a single disease. Different biological problems can produce a very similar pattern of symptoms.Researchers are still trying to understand why this happens, but several mechanisms appear to play a role.Some people have damage to the small nerve fibres that control blood vessel tightening.
Others appear to have a lower circulating blood volume, making it harder to maintain blood flow when standing.Some develop an exaggerated adrenaline response, causing a racing heart, tremor and feelings of being constantly “switched on.”
Increasing evidence also suggests that immune system changes and autoimmune mechanisms may contribute in some people, particularly following viral infections.It’s also possible for more than one mechanism to exist at the same time, which helps explain why no two people experience POTS in exactly the same way.
Why Does Long COVID Cause POTS?
This is one of the biggest areas of Long COVID research.Doctors first noticed that many people who had recovered from COVID-19 were developing symptoms that looked remarkably similar to POTS.
People who had never experienced dizziness before suddenly struggled to stand.Their heart raced.
They became exhausted after being upright for only short periods.Researchers are still investigating exactly why this happens, but current evidence suggests COVID-19 may disrupt the autonomic nervous system in several ways. These include immune dysregulation, injury to small nerve fibres, changes in blood vessel function and, in some people, autoimmune responses.
Not everyone with Long COVID develops POTS.Likewise, not everyone with POTS has Long COVID.
But the overlap between the two conditions is now well recognised.
Conditions That Often Overlap
POTS rarely arrives completely on its own.Many people also live with other conditions that affect connective tissue, the immune system or the nervous system.
These include hypermobile Ehlers-Danlos syndrome (hEDS), hypermobility spectrum disorders, Mast Cell Activation Syndrome (MCAS), small fibre neuropathy, Sjögren’s syndrome, lupus, ME/CFS and Long COVID.
Researchers are still trying to understand why these conditions overlap so often.
The important message is that recognising one diagnosis should not stop doctors looking for others. Understanding the full picture often leads to better management.
How Is POTS Diagnosed?
One of the most frustrating parts of POTS is that many routine tests can come back completely normal.Your ECG may be normal.Your echocardiogram may be normal.Your blood tests may be normal.
That doesn’t mean your symptoms aren’t real.Those tests are looking for structural heart disease, rhythm abnormalities or other medical conditions. They don’t measure how your heart and blood pressure respond when you stand.
Diagnosis usually begins with a careful history and a standing test.Many clinicians perform an Active Stand Test, measuring heart rate and blood pressure while lying down and then again after standing.
In adults, POTS is generally considered when heart rate increases by at least 30 beats per minute within ten minutes of standing, without a significant drop in blood pressure. Different criteria apply to teenagers.
Some people may also be referred for tilt-table testing or specialist autonomic assessment.
How Is POTS Managed?
There is no single treatment that works for everyone.Management is usually about improving how your body copes with being upright while identifying any underlying problems that can also be treated.
For many people, simple changes make a meaningful difference.Drinking enough fluids, increasing salt intake where appropriate, wearing compression garments and avoiding prolonged standing or excessive heat can all reduce symptoms.
Some people also benefit from smaller meals, cooling strategies and learning how to pace activities throughout the day.When lifestyle measures aren’t enough, medications such as fludrocortisone, midodrine, beta-blockers, ivabradine or pyridostigmine may be considered by a specialist. The choice depends on your individual symptoms and medical history.
There is no “best” treatment for POTS. Finding the right combination often takes time.
Living With POTS
Living with POTS isn’t just about managing a racing heart. It’s about learning how your own body behaves.
You begin to notice that standing in a queue is harder than walking.That hot weather makes everything worse.
That showers can leave you exhausted. That eating a large meal sometimes makes you feel faint.
Understanding these patterns doesn’t make the condition disappear.But it does make it feel less mysterious.
For many people, that’s the first step towards regaining confidence and building a life around the condition instead of constantly being surprised by it.
Outlook
Recovery looks different for everyone. Some people improve substantially over time.
Others continue to experience symptoms that fluctuate from day to day or month to month.For people whose POTS developed after COVID-19, research is still trying to understand why some recover while others remain unwell.Although there is currently no universal cure, early recognition, appropriate management and understanding your own triggers can often reduce symptoms and improve quality of life.
Key Takeaways
- POTS is a disorder of the autonomic nervous system, not simply a fast heart rate.
- Symptoms often include dizziness, palpitations, fatigue, brain fog and exercise intolerance.
- Many people develop POTS after viral infections, including COVID-19.
- A normal ECG or blood test does not rule it out.
- Management usually combines lifestyle changes, pacing and, in some cases, medication.
Bottom Line
POTS and orthostatic intolerance are real, measurable conditions affecting multiple systems.
Understanding them helps patients regain control—and helps clinicians provide appropriate care.
FAQs
Can you have POTS with normal heart tests?
Yes. Many people with POTS have completely normal ECGs, echocardiograms and routine blood tests. These investigations look for structural heart disease or rhythm problems, but they do not measure how your heart and blood pressure respond when you stand up. That’s why an Active Stand Test or tilt-table test is often needed to diagnose POTS.
Can Long COVID cause POTS?
Yes. Increasing evidence shows that some people develop POTS after COVID-19. Researchers believe the virus may disrupt the autonomic nervous system through several mechanisms, including immune dysregulation, small fibre nerve injury and changes in blood vessel regulation. Not everyone with Long COVID develops POTS, but the overlap between the two conditions is now well recognised.
Is POTS the same as anxiety?
No. POTS is a recognised disorder of the autonomic nervous system. Although symptoms such as a racing heart, dizziness and trembling can feel similar to anxiety, the underlying cause is different. Anxiety and POTS can occur together, but one should not automatically be mistaken for the other.
Last evidence reviewed: July 2026
Disclaimer
This article is for information and awareness only. It is not medical advice and should not replace professional assessment or treatment. Always consult a qualified healthcare professional before making changes to your care.
Sources and Evidence
This article draws on recognised clinical guidance, expert consensus and peer-reviewed research on POTS, orthostatic intolerance and autonomic dysfunction after COVID-19.
- NICE. COVID-19 rapid guideline: managing the long-term effects of COVID-19 (NG188).
- Heart Rhythm Society. Expert Consensus Statement on the Diagnosis and Treatment of Postural Tachycardia Syndrome.
- Canadian Cardiovascular Society. Position Statement on Postural Orthostatic Tachycardia Syndrome and Related Disorders.
- Relevant peer-reviewed studies on autonomic dysfunction and POTS following COVID-19.
Research into post-COVID autonomic dysfunction is still evolving. Where evidence is incomplete, this article distinguishes established clinical guidance from emerging explanations.
e end, above “Sources and Evidence”:
How This Article Was Prepared
This article was written and reviewed by the LongCovidJourney editorial team using current clinical guidance, peer-reviewed research and lived experience of Long COVID.
LongCovidJourney is an independent educational resource. We explain what is known, make uncertainty clear and update articles as evidence changes. We do not provide diagnosis or personalised medical advice.
Last evidence reviewed: July 2026
This is stronger than claiming “medically reviewed” when no named qualified clinician has performed a formal review.
Google’s own guidance emphasises helpful, reliable, people-first content and asks whether readers can understand who created the content, how it was produced and why it exists. For health content, clear sourcing, honest uncertainty, visible editorial responsibility and accurate author information matter more than trying to manufacture authority through schema alone.
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