Research by David Systrom, a physician at Brigham and Women’s hospital in Boston, might provide a hint as to why. When ME/CFS patients and those with long COVID exercise, Systrom discovered their veins were not moving blood to the heart efficiently, or “priming the pump.” He also found problems with oxygen exchange by the exercising muscle. Through skin biopsies, he sees nerve damage in most patients he tests. “It’s not what we’d expect in pure deconditioning,” Systrom says.
Systrom’s work points to a dysfunctional autonomic nervous system, which controls functions like breathing and circulation, and moves blood and oxygen through the body during and after exercise. He also theorizes that the mitochondria—the parts of our cells that make energy—might not harness oxygen correctly. This all impairs the body’s ability to recover.
Does exercise lead to decline?
The concept of long-term decline after pushing through exertion is well-known amongst providers who treat ME/CFS, and now long COVID.
”Repeated crashes of PEM are like an injury,” Yellman says. “If you stub your toe really hard on the door, you need to let it heal before you put your shoe back on. If you stub it every day, there’s going to be scarring and the toenail isn’t going to grow back.”
The answer, according to physicians familiar with PEM, is pacing—managing daily activities through periods of exertion and rest. It’s critical, Yellman says, to break what he calls “the push-crash cycle,” by learning to recognize energy limits and resting accordingly, which for some people can take months or even years. “I’ve never met a couch potato with this illness,” he says. “A type A personality is honestly a risk factor.”
Clayton Powers, a physical therapist with the University of Utah, first learned about PEM five years ago, while treating patients with postural orthostatic tachycardia syndrome (POTS), a type of autonomic nervous system dysfunction also common in long COVID that can be helped by a form of graded exercise. But he noticed many of his patients weren’t improving with his exercise prescriptions.
He changed his tactics, focusing instead on using heart rate monitors, education, and lifestyle modifications to help patients avoid PEM. “The amount of improvement switching from exercise to focusing more on pacing and energy conservation was drastic,” he says.
With a growing awareness of cases like Lambert’s, patients, advocacy organizations, clinicians, and researchers are pushing back against the National Institutes of Health’s $1.15 billion RECOVER project’s proposed exercise trial for long COVID. Duke University’s Clinical Research Institute, which is coordinating the study, says it’s aimed at combating exercise intolerance, fatigue, and other long COVID symptoms. In an emailed statement, the institute noted that “exercise is not recommended” for those experiencing PEM and claims researchers will carefully monitor for PEM and adapt the program accordingly, but does not explicitly say whether participants with PEM would be excluded.
Putrino and his colleagues developed a specialized rehabilitation program to help some long COVID patients reboot their autonomic nervous systems. In it, patients slowly progress through a series of gentle movements while lying down and doing breathing exercises that promote their “rest and digest” response. Then they move to sitting and upright exercises over the course of a few months. But, unlike graded exercise that encourages patients to push through discomfort, the program is scaled back to about 30 percent of the previous effort at the first sign of PEM, and some people won’t progress past a certain level. Still, according to Putrino, after three months, most participants see fatigue halve and activity tolerance double.
The therapists in Jessica Lambert’s in-patient rehabilitation program employed a similar strategy to help her regain her ability to walk.
”They would start off with me laying down in bed, lifting one leg at a time, then resting,” she says. She eventually progressed to seated activities, like wheelchair yoga, that focused on her ability to better care for herself. Now she’s in physical therapy doing recumbent exercises, and the therapists pull back if she experiences PEM. In a year, she’s gone from being in a wheelchair to being able to walk slowly around the block. “It’s small,” she says, “but it feels huge.”