Fatigue in patients with long Covid has a physical cause

Study finds changes in patients' muscles and suggests that fatigue caused by long Covid has a biological cause. According to experts, the discovery could lead to the search for an appropriate treatment for the disease. People suffering from long Covid have fatigue as one of the most common symptoms. Focused on this, Dutch researchers dedicated themselves to studying the cause of this permanent tiredness, in research now published in the scientific journal Nature.

Involving 25 patients with long Covid and 21 healthy people, the study found “clear changes in the muscles” of individuals with the disease.

“We observed several abnormalities in the patients’ muscle tissue. We saw that muscle mitochondria, also known as the cell's energy factories, work worse and produce less energy”, explained Rob Wüst, from Vrije University in Amsterdam and one of the authors of the study, which points to a biological cause for the symptoms.

Participants had to cycle for 15 minutes, which caused a long-term worsening of symptoms for those suffering from long Covid – something called post-exercise malaise (PEM).

Extreme fatigue occurs after physical, cognitive or emotional exertion with an unknown individual threshold.

The researchers also analyzed blood and muscle tissue one week before the test and one day after the test.

Search for appropriate treatment

The cause of fatigue is “actually biological. The brain needs energy to think. Muscles need energy to move”, confirms Michèle van Vugt, from the University Medical Center (CMU) in Amsterdam.

This discovery means, according to her, that it is now possible to begin research into a suitable treatment for those suffering from long Covid.

While one theory about long-haul Covid-19 is that coronavirus particles can remain in the body, researchers have so far seen no evidence of this in muscles.

Furthermore, they observed that the heart and lungs function well in patients, meaning that the lasting effect on fitness is not caused by abnormalities in these organs.

Patients with the disease should monitor their physical limits and not exceed them, although they can walk or ride an e-bike to maintain a certain level of fitness, keeping in mind that each person has a different limit, said Brent Appelman of the CMU , in a statement.

Some classic forms of rehabilitation and physiotherapy are also counterproductive to the recovery of these patients, as symptoms can worsen after physical exertion, added Van Vugt.

Double the problem in low and middle income countries

Much of the world's research on long Covid is carried out in wealthy regions, and data on the prevalence or severity of the disease in other locations is more limited.

“The main issue about long Covid-19 in low- and middle-income countries is that there are few studies,” says Theo Vos, an epidemiologist at the Institute for Health Metrics and Evaluation in Seattle, Washington. “But wherever people look at the problem, they find it.” In Brazil, for example, according to estimates, more than 4 million people have long Covid.

So far, the evidence suggests that the prevalence of long Covid in low- and middle-income countries may be similar to that in richer countries, although in both scenarios the numbers vary greatly. But the scarcity of research into the disease in less wealthy countries creates a double problem.

The lack of information on prevalence and risk factors leaves “caregivers” of the disease in difficulties: few doctors recognize the existence of prolonged Covid-19.

The lack of data also hampers efforts to research disease mechanisms and adapt treatments. “You need data to act,” says Waasila Jassat, a public health expert at Genesis Analytics, a consulting firm in Johannesburg, South Africa. “You need evidence to make the case for services, and you can't just use other people's data.” countries.”

Symptoms

Although most people infected with the Sars-Cov-2 coronavirus recover within a few weeks, it is estimated that around one in eight people will have long Covid, with symptoms such as brain fog, fatigue, exercise intolerance or postural tachycardia syndrome. orthostatic.

Long Covid is a complex condition caused by coronavirus infection. It has been associated with more than 200 symptoms. The severity of the illness can vary, and for many people, symptoms come and go; There are days when they are able to live as before, but from one day to the next they discover that the disease has returned with full force.

According to some definitions, long Covid consists of any symptom that appears or persists for more than three months after the initial infection.

According to a 2023 survey by Nature, around 65 million people around the world have some symptom of this syndrome. The scientific journal article also highlighted that unvaccinated individuals are at greater risk of developing the problem.

lr/ek (Efe, Nature, Reuters)