Understanding Orthostatic Intolerance (OI) After Long COVID
If you’ve been told you don’t have Postural Orthostatic Tachycardia Syndrome (POTS) but still feel dizzy, exhausted or unwell every time you stand up, you’re not alone. Many people with Long COVID experience orthostatic intolerance (OI) a pattern of symptoms that become worse when standing and improve when sitting or lying down. POTS is one cause of orthostatic intolerance, but it isn’t the only one. That means you can have genuine, disabling symptoms without meeting the formal diagnostic criteria for POTS. Understanding the difference can help explain why your doctor may still recommend treatments such as fluids, salt, compression stockings or medication, even when your test results don’t fit neatly into a single diagnosis.
Key Takeaways
- Orthostatic intolerance describes symptoms that worsen when you’re upright and improve when you lie down.
- POTS is one form of orthostatic intolerance, but not everyone with OI has POTS.
- A “normal” or borderline test result doesn’t always reflect how you feel in everyday life.
- Doctors often treat symptoms and underlying physiology, not just diagnostic labels.
- Many people with Long COVID experience orthostatic intolerance even without a formal POTS diagnosis.
“Good News… You Don’t Have POTS.”
You wait months for an appointment at an autonomic clinic. You finally have your assessment. Your heart rate is monitored. Perhaps you even have a tilt table test. The consultant smiles and says:
“The good news is you don’t have POTS.”
You should feel relieved. Instead, you leave more confused than when you arrived. Standing in a supermarket queue still makes you feel faint. You still need to sit down to brush your teeth. Cooking dinner still feels harder than it should. Your body hasn’t changed simply because the test result didn’t meet a diagnostic threshold.
If this sounds familiar, you’re asking exactly the right question. If it isn’t POTS, why do I still feel so awful standing up?
Can You Feel This Ill Without Having POTS?
The short answer is yes. One of the biggest misunderstandings is thinking that POTS and orthostatic intolerance are the same thing. They’re not. Orthostatic intolerance describes what happens when your body struggles to cope with being upright. Symptoms often improve when you sit or lie down. POTS is one specific condition that can cause orthostatic intolerance, but it isn’t the only one.
Think of it like this: That distinction matters because it explains why two people can have almost identical symptoms, yet only one receives a diagnosis of POTS.
If you’d like to understand how Long COVID can affect the autonomic nervous system, read our guide to Dysautonomia.
“My Heart Rate Only Went Up by 28 Beats Per Minute”
This is one of the most common stories we hear. Your heart rate increases when you stand, but not quite enough to meet the diagnostic criteria for POTS. Maybe it went up by 28 beats per minute instead of 30.
It’s easy to become fixated on those numbers and wonder whether two extra beats would have changed everything. In reality, diagnostic thresholds are designed to help doctors classify conditions consistently. They aren’t a measure of how much your symptoms affect your life.
Someone whose heart rate rises by 28 beats per minute may still struggle to stand long enough to wash their hair, prepare a meal or wait at a checkout. Someone else who meets the diagnostic threshold may have much milder symptoms.
Autonomic function also isn’t fixed. Heat, dehydration, recent illness, poor sleep, medications, hormones and even how active you’ve been that day can influence how your body responds during testing.
A clinic appointment captures one moment in time. It doesn’t always capture your everyday life.
My Tilt Table Test Was Normal… So What Now?
Hearing that your tilt table test was “normal” can be incredibly frustrating when standing still still makes you feel awful.
The important thing to remember is that a test measures how your body behaved on that day. Your symptoms, however, may change depending on the weather, hydration, sleep, medications, recent activity or whether you’re having a better or worse week.
That doesn’t mean the test was wrong. It simply means it is one piece of the puzzle, not the whole picture.
Some autonomic clinics also use the NASA Lean Test as part of their assessment. It’s a simpler standing test that can sometimes reveal patterns seen in everyday life. If you’ve been asked to perform one—or are curious how it differs from a tilt table test—we explain it in our article What Is the NASA Lean Test?
The goal isn’t to “pass” or “fail” a test. It’s to understand why your body struggles when you’re upright.
Why Am I Still Being Treated If I Don’t Have POTS?
This often surprises people. After saying you don’t have POTS, your specialist might still recommend drinking more fluids, adjusting your salt intake, wearing compression garments or prescribing medication such as ivabradine or midodrine. At first, that feels contradictory. Then comes the “aha” moment.
Doctors don’t only treat diagnoses they also treat physiology.
If your symptoms consistently appear when you’re standing and improve when you lie down, your specialist may recommend treatments that help your body cope with being upright, even if you don’t meet the formal criteria for POTS.
The goal isn’t to treat a label. It’s to help you feel and function better. If you’d like to understand why compression garments can help some people, we’ve covered that in our guide to Compression Stockings for Long COVID and POTS.
Why Was I Told to Eat More Salt?
This is another moment that leaves many people scratching their heads. For years we’ve been told:
“Too much salt is bad for you.”
Then an autonomic clinic says:
“Try increasing your salt.”
How can both be true? The answer is that public health advice is written for the general population, while autonomic specialists are treating an individual medical problem.
For some people with orthostatic intolerance, increasing salt alongside fluids can help the body retain more water and improve circulating blood volume. That may make standing easier.
It doesn’t mean everyone with Long COVID should eat a high-salt diet, and it isn’t appropriate for everyone. Your specialist will consider your overall health before making recommendations.
Once you understand why the advice is different, it no longer feels like a contradiction.
Does This Sound Like You?
Sometimes the most reassuring thing isn’t another medical explanation. It’s realising other people do the same things.
- You scan cafés for the nearest chair.
- You lean on the supermarket trolley even when it isn’t heavy.
- You rest against the kitchen counter while cooking.
- You sit down to brush your teeth or dry your hair.
- You avoid queues whenever possible.
- You feel immediate relief when you lie flat.
- You keep shifting your weight because standing still feels impossible.
None of these habits mean you’re lazy. Many are instinctive ways your body tries to make standing more manageable. If one thing surprised you, it might be this: You’re probably adapting far more than you realise.
Many people don’t realise how much they’ve adapted until someone points it out. What once felt like temporary adjustments gradually become everyday habits.
One example is using a stool. Whether it’s while cooking, getting dressed or brushing your teeth, many people find that sitting on a stool feels surprisingly different from standing. There’s a simple physiological reason for this, which we explore in our article Why Does Sitting on a Stool Feel So Much Easier Than Standing?
Focus on the Pattern, Not Just the Diagnosis
It’s completely understandable to want a diagnosis. Having a name for what’s happening can be reassuring.
But there’s another question that’s just as important. What pattern is your body showing you?
Do your symptoms appear when you stand? Do they improve when you sit or lie down?
Does heat make everything worse? Do fluids help? Does a large meal leave you feeling lightheaded?
These patterns often tell your healthcare team as much as any single number on a clinic report.
They also help you recognise triggers and understand your own body better.
You Might Also Be Wondering…
Can you have orthostatic intolerance without POTS?
Yes. POTS is one cause of orthostatic intolerance, but it isn’t the only one. Many people experience orthostatic symptoms without meeting the formal diagnostic criteria for POTS.
Can a normal tilt table test miss orthostatic intolerance?
A tilt table test provides valuable information, but it reflects your body’s response on that particular day. Your symptoms, medical history and other assessments all contribute to the overall picture.
Can Long COVID cause orthostatic intolerance?
Yes. Research suggests that autonomic dysfunction is one of the mechanisms that can contribute to persistent symptoms after COVID-19, although not everyone with Long COVID experiences orthostatic intolerance.
Will it get better?
Some people improve gradually as the underlying condition improves, while others continue to experience symptoms for longer and benefit from ongoing management strategies. Recovery varies from person to person.
Will I Have Autonomic Dysfunction for the Rest of My Life?
Not necessarily. The answer depends on the underlying cause. Some people recover as the condition triggering their autonomic symptoms improves, while others continue to experience symptoms for longer and learn ways to manage them. In Long COVID, recovery is highly variable, and researchers are still working to understand why some people improve more quickly than others. Your healthcare team can advise you based on your individual situation.
What the Evidence Says
Research from Long COVID clinics around the world has shown that orthostatic intolerance is common after COVID-19. While some people meet the criteria for POTS, others experience similar symptoms without fitting neatly into a single diagnosis. Current guidance recommends looking at the whole clinical picture—including symptoms, examination and testing—rather than relying on one heart rate measurement or one investigation. As research continues, our understanding of autonomic dysfunction after COVID is steadily improving.
Continue Your Journey
→ What Is Dysautonomia? ( coming soon)
→ Why Does My Heart Race When I Stand Up?
→ Why Do I Feel Better When I Lie Down? Understanding Long COVID, POTS and Blood Flow
→ Compression Stockings for Long COVID and POTS (coming soon.)