What Triggers POTS Flare-Ups, and What to Do When One Hits

What Is a POTS Flare?

Our team sees a POTS flare as the body's compensation working under extra load. When you stand, the brain needs its blood supply held steady, and the fast heart rate in POTS is the rescue that holds it. POTS is that rescue succeeding, and orthostatic hypotension, where blood pressure falls on standing, is the rescue failing. A flare is a stretch when more load lands on that rescue than it can comfortably carry.

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What Triggers a POTS Flare?

In our team's experience, a single trigger is often manageable. A hot day, a big lunch and a long wait on your feet together can stack past what the rescue covers.

Standing still

Standing pulls blood toward the legs, and the brain's supply has to be defended in the first moments of a stand. In a study of 54 people with POTS and 32 healthy controls, half the POTS group developed low CO2 while upright. In that half, the lowest brain blood velocity was 48 cm/s, against 61 in people with POTS and normal CO2 and 60 in controls, and the drop came before the CO2 fell (Stewart, 2023). That study looked at the act of standing up. Our team sees standing still as the hardest version, because still leg muscles do less to push blood back toward the heart. For how a normal standing heart rate compares with POTS, see why your heart races when you stand up.

Meals

A meal moves blood to the gut. In 11 people with POTS and 10 controls, a test meal raised heart rate and blood flow in the main gut artery in both groups, and the authors note that orthostatic symptoms often get worse after eating in POTS (Tani, 2000). Carbohydrate is the load that has been tested. In 12 women with POTS who felt worse after meals, upright heart rate rose 21.2% after a 75 g glucose drink, against 6.0% in 13 healthy women, and only 1 gut hormone, GIP, tracked the worsening (Breier, 2022). That was a sugar drink in a small group, and the authors say the precise mechanism is unknown. Our team's practical read is that smaller meals with less refined carbohydrate put less on the rescue at once. For nausea, bloating and the rest of the gut story, see why POTS wrecks your digestion.

Heat

Heat reduces how long even healthy people tolerate being upright. A review concluded that heat stress "profoundly and unanimously reduces orthostatic tolerance" (Schlader, 2016). Hot showers, summer afternoons and overheated rooms all count. The mechanism, and how to build tolerance back, is on our page about why heat makes POTS worse.

Illness and infection

A viral infection may start POTS. A report from a 2019 NIH expert consensus meeting says onset "may be precipitated by immunological stressors such as a viral infection" (Vernino, 2021), and a review of POTS after COVID-19 says it may be triggered by viral infection (Ormiston, 2022). Those papers describe how POTS begins. Our team also sees colds, flu and other infections bring on flares in people who already have POTS. In the clinic's view, the body sends extra energy and blood flow to the immune response, and that raises the load on the same rescue that holds brain blood flow steady. That's why our team looks at the load underneath the heart rate, because a plan that only chases the heart rate number leaves that load in place.

The menstrual cycle

A 2015 study notes that women with POTS report that their tolerance for standing shifts across the cycle (Stickford, 2015). In a questionnaire of 65 women with POTS and 95 healthy women, both groups felt most lightheaded during their period, and the POTS group was more lightheaded in every phase (Peggs, 2012). In a lab study of 10 women with POTS and 11 healthy women, near-fainting was more common in the early follicular phase than in the mid-luteal phase (Fu, 2010). The 2 studies measured different things and don't settle which phase is worst. A study of 10 women with POTS found that sympathetic nerve activity stayed the same across the cycle while blood pressure and vessel tightening shifted, so the cause is still unknown (Stickford, 2015). If your flares cluster around your period or another part of the month, a few cycles of tracking will show your own pattern.

Sleep and mornings

Our team often hears that a bad night sets up a bad day. We found no study that tests poor sleep as a flare trigger, so that link is our team's observation. Mornings have their own pattern, covered in our page on why POTS is worse in the morning, and sleep's role in recovery is in sleep, neuroplasticity and POTS.

Anxiety, overexertion, mast cell flares and hyperadrenergic POTS can also bring on symptoms, and each is covered in depth: POTS vs anxiety, why standard exercise advice fails POTS patients, how mast cells and the autonomic system drive each other and hyperadrenergic POTS.

What Should You Do During a POTS Flare?

Start by taking load off the rescue. Lie flat, or sit with your legs raised, so your brain isn't fighting gravity for its supply. Get out of the heat and cool down. Then remove whatever trigger you can, whether that's sitting down partway through a long errand, stopping halfway through a heavy meal or resting through a cold. If your care plan already includes extra fluids and salt, a flare is the time to use it. Those steps are our team's standard flare plan.

Muscle moves may help too. A review of non-drug POTS care lists squeezing a rubber ball, crossing the legs, muscle pumping and squatting as maneuvers that "may also be effective in preventing orthostatic intolerance and managing acute clinical symptoms" in POTS, and it adds that randomized trials are still needed (Fu, 2018). We found no trial that tested flare care itself, so these steps rest on physiology and on what our team sees in the clinic.

• Ball squeeze. Squeeze a rubber ball or your fists hard for a few seconds, then release.
• Leg cross. Cross your legs while standing and tense your thighs and buttocks.
• Squat. Drop into a squat, or sit, as soon as the lightheadedness starts.
• Legs up. Lie flat with your legs raised on pillows or a wall.

Ball squeeze, leg crossing, muscle pumping and squatting are listed as possible help for acute symptoms in a review that calls for trials (Fu, 2018). Lying with the legs up is our team's advice. Hold times and technique are our team's teaching.

Medications help some people with POTS. Their ceiling is real: there are currently no FDA-approved medications for POTS, and evidence for many of the drugs used is "not robust" (Vernino, 2021). In our team's view, a drug that calms the heart rate eases the symptom while the load underneath stays where it was. Medication can serve as a bridge while our team works on that load alongside your prescriber.

When Is a Flare Something More?

A new symptom, or a pattern that keeps changing, deserves testing. That report says the workup for suspected POTS should "exclude conditions that could cause or mimic the syndrome" (Vernino, 2021). If you've never had formal autonomic testing, it matters: at 1 referral center, the workup found no cardiovascular autonomic disorder in half the people newly referred after COVID-19 infection or vaccination, 49 of 101 (Leys, 2025).

When should you go to the hospital for a POTS flare?

Call 911 or go to the ER for chest pain, trouble breathing, fainting with an injury, fainting while lying down or during exercise, fainting that doesn't clear when you lie flat, or sudden severe symptoms such as weakness on one side, trouble speaking or the worst headache of your life. If you're ill and can't keep fluids down, get seen the same day. For a new symptom that isn't an emergency, call your doctor soon.

Flares that keep coming back mean the load is worth mapping. Our team tests how brain blood flow, breathing and heart rate respond when you stand, to find which part of the system is carrying the most.

POTS Flare-Ups: FAQ