A new study conducted by researchers from Amsterdam UMC and Vrije Universiteit Amsterdam (VU) has discovered a biological cause for the persistent fatigue experienced by patients with long COVID. The study focused on the mitochondria in muscle cells, which were found to produce less energy compared to healthy individuals .
Mitochondria are membrane-bound organelles responsible for generating the majority of the chemical energy needed to power a cell's biochemical reactions . They are often referred to as the "energy factories" of the cell. In patients with long COVID, the researchers observed abnormalities in the muscle tissue, specifically in the mitochondria. These abnormalities resulted in reduced mitochondrial function and energy production .
The study involved 25 long COVID patients and 21 healthy control participants. They were asked to cycle for 15 minutes, which caused a long-term worsening of symptoms in the long COVID patients, known as post-exertional malaise (PEM). This extreme fatigue occurs after physical, cognitive, or emotional exertion beyond an individual threshold.
The researchers analyzed the blood and muscle tissue of the participants one week before the cycling test and one day after the test. They found clear changes in the muscle tissue of the long COVID patients, with the mitochondria functioning less effectively and producing less energy .
The discovery of a biological cause for the fatigue experienced by long COVID patients opens up possibilities for researching appropriate treatments. The brain requires energy for cognitive functions, while muscles need energy for movement. By understanding the underlying biological mechanisms, researchers can now focus on developing targeted treatments for long COVID patients.
Other Findings and Recommendations
The study also addressed other aspects of long COVID. The researchers did not find any indications of coronavirus particles remaining in the muscles of long COVID patients. Additionally, the heart and lungs of the patients functioned well, suggesting that the long-lasting effects on fitness are not caused by abnormalities in these organs .
The researchers emphasized that exercising is not always beneficial for patients with long COVID. They advised patients to be mindful of their physical limits and avoid exceeding them. Light exertion, such as walking or riding an electric bike, can help maintain some physical condition without worsening symptoms. However, it is important to note that every patient has a different limit, and individualized approaches are necessary.
Classic forms of rehabilitation and physiotherapy may be counterproductive for the recovery of long COVID patients due to the potential worsening of symptoms after physical exertion. Therefore, it is crucial for healthcare professionals to consider the specific needs and limitations of each patient when designing treatment plans.