POTS, or postural orthostatic tachycardia syndrome, most commonly develops after a viral infection, surgery, pregnancy, or other physical stressor that disrupts the body’s ability to regulate heart rate and blood flow when you stand up. About 89% of diagnosed patients are female, and the average age at diagnosis is 23, though cases range from age 11 to 51. There isn’t one single cause. Instead, several different biological pathways can lead to the same result: your heart rate jumps excessively when you go from lying down to standing.
What POTS Actually Is
POTS is defined by a sustained heart rate increase of at least 30 beats per minute within 10 minutes of standing, without a significant drop in blood pressure. For teenagers (ages 12 to 19), the threshold is higher: at least 40 beats per minute. The heart rate spike must come with symptoms like dizziness, lightheadedness, brain fog, or feeling faint, and those symptoms need to improve quickly when you lie back down.
The condition isn’t a single disease so much as a collection of problems that all produce the same outcome. Your nervous system, blood volume, blood vessels, or immune system can each malfunction in ways that cause your heart to race when you’re upright. Understanding which pathway is involved helps explain why different people develop POTS through different routes.
Viral Infections Are the Most Common Trigger
The most well-documented path to POTS is through a viral infection. COVID-19 brought this connection into sharp focus. In one study comparing long-COVID patients with other groups, every single long-COVID participant (100%) met the criteria for POTS, compared to 43% of those whose illness started with Epstein-Barr virus and 50% of those with a gradual, unexplained onset. Epstein-Barr virus (the virus behind mono) has long been recognized as a POTS trigger, but COVID-19 appears to provoke the condition at notably higher rates.
The mechanism likely involves the immune system. During or after an infection, the body can produce antibodies that mistakenly target receptors involved in heart rate and blood vessel control. Research published in the Journal of the American Heart Association found that 89% of POTS patients had elevated antibodies against a receptor that helps regulate blood vessel constriction, and 53% had elevated antibodies against a receptor involved in nervous system signaling. Only 9% of patients showed no antibody elevations at all. This suggests that for many people, POTS is at least partly an autoimmune condition triggered by the body’s response to infection.
Physical Stressors Beyond Infection
Viral illness isn’t the only trigger. Among POTS patients who could identify a specific event that started their symptoms, about 8% pointed to pregnancy. Hormonal shifts play a significant role in the condition more broadly. POTS disproportionately affects women of reproductive age, with symptoms frequently appearing around puberty, worsening before or during menstrual periods, and sometimes emerging for the first time during or after pregnancy.
Surgery, physical trauma, and concussions are also recognized triggers, though less thoroughly studied. The common thread seems to be any major physiological stress that pushes the autonomic nervous system (the system that controls unconscious functions like heart rate, digestion, and blood pressure) past a tipping point. In some people, the system recovers. In others, it doesn’t fully reset, and POTS symptoms persist.
Three Ways the Body Breaks Down
Once triggered, POTS tends to follow one of three main patterns, and some people have features of more than one.
Neuropathic POTS is the most common subtype. The small nerve fibers that tell blood vessels to tighten when you stand stop working properly. Without that signal, blood pools in your legs and abdomen instead of returning to your heart. Your heart compensates by beating faster to maintain blood flow to your brain. Over time, this compensatory mechanism can become overwhelmed, making symptoms progressively worse.
Hyperadrenergic POTS involves excess production of norepinephrine, one of the body’s “fight or flight” chemicals, or a failure to clear it from the bloodstream after it’s released. This creates a state of constant nervous system overdrive. People with this subtype often experience tremors, anxiety, and surges of high blood pressure alongside the rapid heart rate.
Hypovolemic POTS centers on low blood volume. The majority of POTS patients have some degree of reduced blood and plasma volume. Normally, your kidneys respond to low blood volume by activating a hormonal system that retains salt and water. In many POTS patients, this system doesn’t activate properly. Levels of the hormones that should trigger salt retention stay inappropriately low even when blood volume is depleted. Researchers call this the “renin-aldosterone paradox.” The result is a vicious cycle: low blood volume means less blood returning to the heart when you stand, which triggers a faster heart rate, which worsens symptoms.
Genetics and Family Patterns
A small number of POTS cases have a clear genetic component. Researchers identified a specific gene mutation in identical twins with orthostatic intolerance that knocked out more than 98% of a protein responsible for clearing norepinephrine from the space around nerve cells. When the body can’t reabsorb norepinephrine efficiently, it accumulates and overstimulates the cardiovascular system.
In the affected family, multiple members who carried even one copy of the mutant gene had significantly higher heart rates and norepinephrine levels while standing compared to family members without the mutation. This mutation is rare, but it demonstrates that inherited differences in how your body handles stress chemicals can predispose you to POTS. More broadly, POTS does appear to run in families, though in most cases the genetic contribution is likely a combination of many small risk factors rather than a single gene.
Conditions That Overlap With POTS
POTS rarely appears in isolation. It frequently coexists with Ehlers-Danlos syndrome, a connective tissue disorder that makes joints overly flexible and blood vessels more stretchy than normal. Stretchier veins pool blood more easily, which helps explain why these two conditions travel together so often.
Mast cell activation syndrome (MCAS), a condition where immune cells release excessive amounts of histamine and other inflammatory chemicals, also overlaps significantly. Among patients who have both POTS and Ehlers-Danlos syndrome, 31% also meet the criteria for MCAS, compared to just 2% of those without POTS. This triad of POTS, Ehlers-Danlos, and MCAS appears frequently enough that clinicians now screen for all three when one is present.
Deconditioning: Cause or Consequence
Physical deconditioning, the loss of cardiovascular fitness that happens when you stop being active, plays a complicated role in POTS. For some people, prolonged bed rest after surgery or illness is the event that tips them into the condition. Reduced fitness shrinks blood volume and weakens the heart’s ability to pump effectively, both of which worsen the heart rate response to standing.
But deconditioning is also a consequence of POTS. When standing makes you dizzy and exhausted, you naturally spend more time sitting or lying down, which further reduces your fitness and blood volume. This creates a feedback loop that can make the condition progressively worse over time. Breaking that cycle through carefully graded exercise programs is one of the most effective management strategies, but it’s a slow process that typically takes months of gradual progression.