POTS Brain Fog: Causes and What Helps

Why Does POTS Cause Brain Fog?

In our team's view, the fast heart rate in POTS is a rescue for brain blood flow. In our team's view, POTS is that compensation succeeding and orthostatic hypotension is it failing. Blood pressure can still dip briefly in the first moments of standing in POTS before it recovers. The question for fog is what happens to the brain's supply in the seconds before the heart rate climbs.

In a tilt-table study, 11 patients with suspected POTS, whose chief complaint was breathlessness when upright, were compared with 10 healthy controls on a 70 degree head-up tilt. In the POTS group, brain blood flow velocity fell first, and the drop came 17 ± 6 seconds before breathing sped up and end-tidal CO2 (the CO2 measured at the end of each breath out) began to fall (Del Pozzi, 2014). Healthy controls also had a drop, though a smaller one. A 2023 paper from the same research group states in its title that an anticipatory central command on standing lowers brain blood velocity and causes low CO2 in people with POTS who breathe fast and deep (Stewart, 2023). The first study was small and enrolled only people whose main complaint was breathlessness. Most of the studies here on brain blood flow, and the 2013 survey, come from one research group in New York.

Lying Standing

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A second small study, of 11 people with POTS and 9 controls on a graded tilt, linked unsteady, swinging brain blood flow with worse thinking. N-back memory testing showed progressively compromised memory, reduced functional hyperemia and reduced neurovascular coupling (Stewart, 2015). Neurovascular coupling is the close timing and regional match between nerve activity and blood flow in the brain (Phillips, 2016). When that match slips, the part of the brain doing the work doesn't get the extra supply it asks for.

Our team places the root problem one level above any single vessel or breathing pattern. The autonomic nervous system runs the heart, the blood vessels, breathing and the kidneys at the same time, so one upstream control problem can show up as fog, gut trouble and a racing heart at the same time. That's why our team looks at how the brain coordinates those systems and treats brain fog as one result of that coordination.

What Does POTS Brain Fog Feel Like?

In a survey of 138 people who reported a POTS diagnosis, ages 14 to 29, recruited from social media, the top descriptors for brain fog were "forgetful," "cloudy," and "difficulty focusing, thinking and communicating" (Ross, 2013). The sample was self-selected online and mostly women, so it reflects the people who answer POTS surveys more than everyone with the condition. For how common fog is in POTS surveys, and for brain fog without a POTS diagnosis, see our article on brain fog causes.

The 2013 survey itself calls it an "ill-defined cognitive impairment referred to by patients as 'brain fog'" (Ross, 2013), which is one reason our team measures what the body is doing while the fog is present.

Why Does Standing Make POTS Brain Fog Worse Than Sitting?

A 2020 study measured thinking during active standing in 87 people with POTS and 39 controls. The POTS group had lower executive function (t-score 48 ± 11 against 55 ± 10 in controls, p = 0.009) and worse attention (reaction speed 2.78 ± 0.11 against 2.69 ± 0.06, p < 0.001) while standing (Miller, 2020).

• Controls (39)55
• POTS (87)48

Group means during active standing. Bars drawn on a 0 to 70 axis; t-scores are set so the population average is 50. Cross-sectional study of 87 people with POTS and 39 controls (Miller et al., Autonomic Neuroscience 2020, PMID 32526639).

Working memory also slipped as the tilt became steeper. In 25 young people with chronic fatigue syndrome and POTS, n-back performance fell as the tilt progressed from lying flat to 75 degrees, compared with 20 controls (Stewart, 2012), though all of them also had chronic fatigue syndrome.

Why Can POTS Brain Fog Hit When You're Sitting or Lying Down?

A review of the cognitive literature in POTS notes that many patients report incapacitating cognitive dysfunction, or brain fog, "even while lying down or seated" (Raj, 2018). In a 30-minute sustained mental task done sitting, brain blood flow velocity fell more in 22 people with POTS than in 18 controls (Wells, 2020). The study was small, and it tested a long stretch of hard mental work.

Our team reads both findings together. Standing makes the supply problem larger, and sustained thinking puts its own demand on the brain's supply, so fog can appear without any change in posture.

Does POTS Cause Memory Loss?

The research describes slowed thinking and working memory that slips under load, more than lost long-term memories. A 2026 MRI study of 18 people with POTS and 20 controls reported that "global screening indicators of cognitive function were preserved," with Montreal Cognitive Assessment scores of 28 ± 1 in POTS and 29 ± 1 in controls (p = .2; Malik, 2026). The 2018 review describes mild to moderate cognitive impairment on standardized neuropsychological batteries (Raj, 2018).

That pattern fits what people describe: the information is still there, and reaching it and holding focus take more effort. A screening test can look normal while the fog is real.

What Makes a Fog Day Worse?

In the same 138-person survey, the triggers people named most often were fatigue, lack of sleep, prolonged standing, dehydration and feeling faint (Ross, 2013). Each was named by a similar share of people, so the survey can't rank them with confidence. Sleep has outside support: in a meta-analysis of short-term sleep deprivation under 48 hours in healthy adults, lapses in simple attention showed a large effect (g = -0.776) (Lim, 2010). That finding comes from healthy volunteers and says nothing about POTS by itself. For sleep, fuel and the other general causes of fog, see our article on brain fog causes.

Is Long COVID Brain Fog the Same Thing?

Long COVID brain fog and POTS overlap in what people feel, and the evidence for how they relate is thin. A 2024 review reports that the prevalence of post-COVID cognitive dysfunction ranges from 10% to 88%, depending on viral variant and hospitalization status among other factors, while the prevalence of long COVID POTS is unknown (Tavee, 2024). Our team tests for the same mechanism in both, because the fog can feel identical while the cause differs from one person to the next.

What Helps POTS Brain Fog?

In the clinic's experience, POTS care often stays centered on the heart. The name has tachycardia in it, the main test is heart rate lying down against standing, and the treatment is mostly medication that acts on the heart. Medications can help, and our team uses them when they do. In our team's view, the ones that act on heart rate, blood volume or vessel tone don't retrain how the brain holds its own blood flow steady. If fog persists on that route, our team looks past the heart rate.

The clinic's approach is to test where the control breaks down and treat that. Our team looks at brain blood flow, breathing and CO2, and the balance inputs that feed the brain's control of posture and circulation. Which of those is off differs from person to person, and that decides what the plan targets.

POTS Brain Fog: FAQ