POTS is a mysterious disorder with a striking resemblance to long-haul COVID-19. Pandemic research may provide treatment clues for both.

Tae Chung, a physical medicine and rehabilitation doctor at Johns Hopkins University, knew what was coming when he started reading last summer about COVID-19 patients who had lingering symptoms.

Chung, who specializes in neuromuscular medicine, immediately saw that the baffling array of symptoms that so called long haulers were reporting was strikingly similar to what he had seen for years among patients with a condition called POTS or postural orthostatic tachycardia syndrome. It often begins after an infection.

Sure enough, Chung, who is among a small number of doctors nationwide who focus on POTS patients, started seeing an influx last fall of COVID-19 survivors with dizziness, intense fatigue, and inability to exercise. “It’s been just exponentially increasing since then,” he said, echoing the experience of other POTS specialists. (Doctors from the Philadelphia area, who do not specialize in POTS, said they have seen only a few such patients.)

Chung expects far more POTS patients this year as some who contracted COVID-19 during the winter wave become long haulers. Patients do not qualify for a POTS diagnosis unless they have been sick for six months.

POTS is a form of dysautonomia, or malfunctioning of the autonomic nervous system. That system regulates all sorts of bodily functions you normally don’t have to think, about including breathing, blood circulation and digestion. A key feature is that heartbeat rises markedly when people stand up after lying down. People don’t always notice this, Chung said, but they do notice that they feel lightheaded and exhausted. There’s considerable overlap between symptoms of POTS and another often-post-viral syndrome that can look like long COVID-19: ME/CFS or myalgic encephalomyelitis/chronic fatigue syndrome.

» READ MORE: Some COVID-19 long haulers have had symptoms for a year. Can they still get better?

Unlike most POTS patients, Claudia Dal Molin, a 37-year-old sports medicine doctor who is the team physician for the University of Maryland, had a vague notion of what POTS was before a doctor told her she had it in July. But that, she said, was “such a far cry from living it.”

For much of the fall, Dal Molin, who was an Orangetheory devotee before she got COVID-19 last March, did her job through telemedicine while lying in bed because she felt so awful when she sat up or stood. She struggled to describe her symptoms other than to say she felt like “garbage.” She wasn’t exactly dizzy or fatigued. “I could have these waves of just feeling so, so, so terrible, like the flu on steroids,” she said. The word that fits, she said, is “malaise.”

She didn’t seriously consider suicide, but the condition, which does not kill people, tested her will to live. “I don’t know if I want to live if this is what living feels like,” she thought.

She saw Chung in December. He put her on a diet high in fluid and salt — yes, lots of salt is part of the treatment for POTS — and she started a very gentle physical therapy program. Things are looking up for her now.

But she’s worried that many of the thousands of other members of a long haulers support group she frequents will find it harder than she did to access doctors who know something about POTS. Primary-care doctors need to educate themselves, she said. “If I’m living it and I missed it,” she said, “God help everybody else.”

Lawyer Lauren Stiles co-founded Dysautonomia International, which advocates for people with POTS, in 2012. She developed symptoms after a concussion, and it took two years to get a diagnosis. Her POTS symptoms faded after she received immunotherapy for Sjogren’s syndrome, an autoimmune disorder. Now a research assistant professor of neurology at Stony Brook University School of Medicine, she is involved in studies of patients with autonomic disorders.

» READ MORE: Sjogren's, a disease you probably can't see or pronounce, wreaks havoc on women

Stiles said her organization’s support groups are “getting flooded with post-COVID POTS patients.” While she is glad for the spotlight on long haulers, she wishes that doctors and researchers had paid more attention to the estimated three million people who had POTS before the pandemic. “Our groups are filled with post-infectious people identical to what is being described in COVID,” she said. If the country had taken those patients more seriously, she said, it would have been better prepared for the pandemic’s aftermath.

She hopes that a new $1.15 billion long COVID-19 research initiative by the National Institutes of Health will benefit other POTS patients. “This is what they’ve been dealing with in the shadows,” she said. “We want COVID patients to get figured out so that everyone can get figured out.”

Doctors described a post-infection syndrome that involved rapid heartbeat or tachycardia and lightheadedness after the Civil War, Stiles said. They called it soldier’s heart or Civil War syndrome. Mayo Clinic researchers gave POTS its current definition in 1993. It has a long list of symptoms, including lightheadedness and even fainting when patients sit or stand, fatigue, brain fog, palpitations, nausea and gastrointestinal problems, insomnia, headaches, sweating and feeling worse after exercise. Hands and feet often turn purple when they’re below heart level. Many patients feel worse after exposure to hot weather or showers.

People who have become badly deconditioned while hospitalized can have similar symptoms. That’s one reason doctors don’t make the diagnosis right away.

The classic way to identify these patients is to use a tilt table, which allows doctors to measure vital signs while patients lie flat and are then tilted upright. In POTS patients, heart rate rises by 30 beats per minute or more after standing for a few minutes. Some doctors say postural changes in heart rate can also be measured without the tilt table. For diagnosis purposes, this is the most important sign of POTS.

“If you don’t have that, you don’t have POTS,” said Pam Taub, a cardiologist who specializes in POTS at the Cardiovascular Institute at University of California San Diego Health. “There are a lot of people that have long COVID that don’t have any abnormalities in their heart rate.” Nonetheless, she said, she has seen a surge of new POTS patients during the pandemic.

Chung fears that heart rate is overemphasized in discussions of the syndrome. Many patients with heart rate changes don’t feel their hearts racing or pounding. What really bothers them is the exhaustion and inability to exercise. He wants to make sure that patients get evaluated for POTS if they develop severe fatigue and exercise intolerance after COVID-19 infection.

There can easily be confusion between POTS and ME/CFS, because they have symptoms in common. Chung said most of his POTS patients have ME/CFS, but chronic fatigue is a broader category that includes people who do not have POTS.

Before COVID-19, POTS largely affected women in their teens and young adulthood. Forty percent to 50% reported an infection of some sort — the syndrome is associated with multiple pathogens — before symptom onset, but it can also start after a concussion or other trauma or pregnancy. POTS experts suspect they are seeing more older patients and more men among long COVID-19 sufferers with POTS symptoms, but this has not been studied.

Brent Goodman, a neurologist who treats POTS patients at Mayo Clinic Arizona, said it’s too early to assume that long haulers have post-COVID-19 POTS. His clinic has seen patients with POTS symptoms and other forms of dysautonomia after COVID-19. “We don’t really know what this is yet,” he said.

There’s also no way yet to know how common it is in COVID-19 patients. Edmond Cronin, a cardiac electrophysiologist at Temple University Hospital, said he has seen some survivors with POTS, but not a huge wave. “If it was something that was very common with COVID, I would think we’d be inundated,” he said.

Doctors say a virus might trigger POTS symptoms by directly damaging the autonomic nervous system. But some suspect that inflammation from infection may do the harm or, even more likely, that infections trigger an autoimmune reaction in some susceptible people.

Jeffrey Boris, a pediatric cardiologist who specialized in POTS at Children’s Hospital of Philadelphia before starting a private practice near Media, found that 45% of 708 POTS patients he studied had a family member with an autoimmune disorder and 14% had a family members with POTS. “There’s definitely something genetic going on there,” he said.

People with POTS can have different underlying physical changes but they generally relate to problems with blood flow. They have low blood volume, and the nervous system does not work properly to make blood circulate throughout the body. When patients stand, their blood tends to pool in their abdomen and legs. The heart compensates by beating rapidly. This deprives organs, including the brain, of the oxygen and nutrients that fresh blood delivers.

Fixing this problem is not easy. As Gustavo Guandalini, a Penn Medicine cardiologist and electrophysiologist pointed out, getting blood to circulate from our toes to our brains while standing is quite a feat under normal circumstances. “We were not designed to live standing up,” he said. All treatments for POTS are “imperfect,” and he thinks it’s important for doctors to set realistic expectations.

Treatment usually starts with lifestyle interventions. Patients are told to drink fluids and eat salt to increase blood volume. Dal Molin felt much better after Chung told her to drink a gallon of water and ingest 4 grams of salt a day. Patients are also told to wear compression stockings and garments that compress the abdomen.

Very gradual exercise programs start with activity that patients can do while lying down and then sitting. Dal Molin’s therapists are now adding meditation and breathing exercises that will re-teach her system to relax when it needs to.

Cronin said these exercises, which can make people uncomfortable, are crucial because inactivity leads to de-conditioning which leads to more symptoms. “If you’re lying in bed all day, understandably, that only makes it worse,” he said.

If those approaches don’t work, doctors can try medicines, although none is specifically approved for POTS. Taub recently completed a clinical trial of ivabradine, a drug that blunts the increase in heart rate without changing blood pressure. It improved heart rate and quality of life in POTS patients. Patients may also try drugs that constrict blood vessels or increase blood volume.

Experts also think that IVIg or intravenous immunoglobulin, a drug used to treat autoimmune disorders, is promising for POTS, but it is expensive and insurers balk at covering it.

POTS resolves in some patients, and others learn to live with their symptoms. “I would say most patients get better, but only 10% to 20% may get back completely to normal or near normal,” Goodman said.

Dal Molin can now see patients while sitting up. She’s thrilled that she can stand and walk a few minutes without feeling sick. She looks forward to being able to take walks in her neighborhood. “I know that this process is going to work,” she said, “and I will not need to be wheeling around in a wheelchair forever.”