Could Your ‘Anxiety’ Actually Be Undiagnosed POTS?
Racing heart. Shaking. Sweating. Feeling wired or on edge. Breathlessness, dizziness, a pounding heart and sometimes a sudden wave of panic.
Most people associate these symptoms with anxiety, and sometimes anxiety is absolutely part of the picture. But they are also common symptoms of Postural Orthostatic Tachycardia Syndrome (POTS), a form of dysautonomia that affects how the autonomic nervous system regulates heart rate and circulation.
If you are trying to understand the causes of anxiety and POTS, and why the two can feel so alike, this guide covers what causes POTS, why it can trigger anxiety-like symptoms, and how to tell the difference.
For some people with POTS, the physical symptoms come first. You stand up, your heart rate rises sharply, you feel light-headed, shaky or breathless, and your body feels as though it has gone into fight-or-flight. Feeling anxious can then be a completely understandable response to what your body is doing.
What is POTS?
POTS is a form of dysautonomia, meaning the autonomic nervous system is not regulating automatic functions as effectively as it should. That system helps control heart rate, blood pressure and blood vessel tone, digestion, sweating, temperature regulation, breathing and the body's stress response.
In adults, POTS is diagnosed when heart rate rises by at least 30 beats per minute within 10 minutes of standing, without a significant fall in blood pressure, alongside chronic symptoms on standing that have lasted at least three months. In 12 to 19 year olds the threshold is 40 beats per minute.
But POTS is much more than a heart rate number. People commonly experience dizziness, palpitations, fatigue, exercise intolerance, brain fog, weakness, nausea, headaches, breathlessness, shakiness and difficulty regulating temperature.
What causes POTS?
There is rarely a single cause. POTS usually develops in someone with an underlying predisposition after a trigger. Common triggers include:
A viral or other infection, including COVID-19
Surgery
Pregnancy and childbirth
Physical trauma or concussion
Significant physical stress
POTS is also associated with hypermobility spectrum disorders and Ehlers-Danlos syndrome, autoimmune conditions, mast cell activation, ME/CFS and small fibre neuropathy.
Several mechanisms are thought to contribute, often in combination. These include low circulating blood volume, excessive blood pooling in the legs and abdomen on standing, autonomic nerve dysfunction, and overactivity of the sympathetic nervous system. Autoimmunity is also being investigated as a driver in some people, though this is still an active research area. Deconditioning can make symptoms worse, but it is not thought to be the primary cause.
Anxiety is not on that list.
Does anxiety cause POTS?
No. On current evidence, anxiety does not cause POTS. POTS is a disorder of autonomic regulation, defined in part by how heart rate and circulation respond to standing. But the two are easily confused because many of their physical symptoms overlap, and they can coexist.
The research supports this. In a psychiatric assessment of people with POTS, rates of anxiety disorders, including panic disorder, were no higher than in the general population. Participants scored as moderately anxious on the Beck Anxiety Inventory but did not show high anxiety sensitivity. Separate physiological work found that the exaggerated heart rate response to standing in POTS is not explained by anxiety.
So why do people with POTS score highly on anxiety questionnaires? A German study found that people with POTS scored higher than controls on questionnaires that include physical items such as palpitations and tremor, but not on those that exclude them. A pounding heart counts as an "anxiety symptom" on the form even when the person was perfectly calm before it started.
Why can POTS feel like anxiety?
When we stand, gravity pulls blood towards the lower body. Normally the autonomic nervous system responds almost immediately by tightening blood vessels and making small adjustments to heart rate, so enough blood keeps reaching the brain. In POTS, that response does not work normally.
The body compensates by increasing heart rate and activating the sympathetic nervous system, which releases noradrenaline. That produces very physical sensations:
A racing or pounding heart
Shakiness or internal trembling
Sweating
Light-headedness
Breathlessness
Chest discomfort
Feeling hot or flushed
Feeling suddenly wired or overstimulated
When your heart is pounding and your body suddenly feels wrong, it is hardly surprising if your brain reads those signals as danger. The physical symptoms can therefore create feelings of anxiety, rather than anxiety necessarily being what started the episode.
Where does hyperadrenergic POTS fit?
Not everyone with POTS has the same physiology. Some people have prominent hyperadrenergic features, meaning particularly strong sympathetic activation. "Adrenergic" refers to adrenaline and noradrenaline, the chemicals behind the fight-or-flight response. In hyperadrenergic POTS, noradrenaline on standing may be elevated (a level above about 600 pg/mL is commonly used) and blood pressure may rise rather than fall.
These people often notice more obvious trembling, sweating, palpitations, blood pressure rises, headaches, flushing, adrenaline-like surges and difficulty sleeping. It is probably the POTS presentation most easily confused with panic or anxiety.
The subtypes overlap, though. Someone can have hyperadrenergic features alongside low blood volume, blood pooling or neuropathic changes, so it is usually more useful to ask which mechanisms are contributing in an individual than to fit everyone into one category.
Is it anxiety or POTS?
Sometimes it is hard to tell, and sometimes it is both. One useful clue is when the symptoms happen. POTS symptoms are often worse with:
Standing for long periods, or getting up quickly
Hot showers, baths or hot weather
Exercise or exertion
Large meals
Alcohol
Dehydration
Illness or poor sleep
Menstruation and hormonal changes
If your "anxiety" consistently appears when you stand, shower, climb stairs or overheat, it is worth considering an autonomic component.
The sequence can also be revealing. Did you feel worried and then notice your heart racing? Or were you feeling completely fine until your heart suddenly started pounding, you became dizzy and shaky, and then you felt anxious? That does not diagnose POTS, but it is useful to discuss with your doctor.
This is not an either/or situation. Someone with POTS can also have an anxiety disorder, and living with unpredictable physical symptoms can make the nervous system more vigilant over time.
What else can cause anxiety-like symptoms?
POTS is one explanation, and it should not be the only one considered. Other causes of a racing heart, tremor and panic-like episodes include:
Thyroid overactivity
Arrhythmias such as tachycardia
Anaemia or iron deficiency
Low blood sugar
Sleep apnoea
Perimenopause
Medication effects or withdrawal, including stimulants and decongestants
Rarely, an adrenaline-secreting tumour (phaeochromocytoma), which is worth excluding if episodes come with high blood pressure
Could this be relevant to you?
If you have been told you are anxious, but you also have a racing heart on standing, dizziness, heat intolerance, exercise intolerance, shaking or adrenaline surges that seem to arrive before any worrying thought, it is reasonable to ask your doctor about POTS or another form of dysautonomia. It does not mean your anxiety is not real. It may simply mean there is another layer to the picture.
How The Autoimmune Clinic can help
At The Autoimmune Clinic we work with people with complex, multisystem presentations, including POTS, mast cell activation, Long COVID, ME/CFS and autoimmune conditions. We look at the wider picture, including immune activation, gut health, nutrient status, hormones and nervous system regulation.
We work online with clients throughout the UK and internationally. If POTS began after COVID-19, you may also find our article on Long COVID, spike protein and MCAS helpful.
