Some people who have had COVID-19, caused by the SARS-CoV-2 virus, continue to experience symptoms long after their initial recovery.
This is often referred to as “long COVID.”
One symptom of long COVID is the reduced ability to exercise. However, experts have been trying to understand why this happens to some people and not others.
New Study on Long COVID
A recent study from UC San Francisco, published in the Journal of Infectious Diseases, has shed some light on this. The researchers found that many people with long COVID could not exercise as much as expected.
The main reason for this was chronotropic incompetence, which means that the heart rate does not increase enough during exercise.
The researchers also found that those with reduced exercise capacity had higher levels of inflammation markers early on in their recovery from COVID-19.
They also found a possible link between reduced heart rate during exercise and reactivation of the Epstein-Barr virus (EBV).
How the Study Was Conducted
Matthew Durstenfeld, MD, MAS, led the study as part of a larger project called the Long-Term Impact of Infection with Novel Coronavirus (LIINC) study.
This project looks at the long-term physical and mental health effects of COVID-19.
The researchers first used echocardiograms, which are tests that show pictures of the heart, to try to find out why some COVID-19 patients had long-term symptoms.
When this didn’t give them the answers they were looking for, they added more tests.
These included tests of lung and heart function during exercise, heart imaging tests, and monitoring heart rhythms over time. They also took blood samples from the study participants.
Findings of the Study
Sixty people took part in the study. They were tested about one and a half years after they had COVID-19.
Almost half of those with long COVID symptoms had reduced exercise capacity, compared to 16% of those without symptoms.
The participants with symptoms had a lower peak VO2, which is a measure of how much oxygen the body uses during exercise.
They also often had chronotropic incompetence, and their inflammation markers and antibody levels in the months following COVID-19 were related to lower peak VO2 levels over a year later.
“Our findings suggest that chronotropic incompetence is one reason why people with long COVID can’t exercise as much,” said Durstenfeld.
“We also found evidence of EBV reactivation in all individuals with chronotropic incompetence. However, we did not find any signs of heart inflammation, heart dysfunction, or serious heart rhythm problems.”
Moving Forward
This study’s findings highlight the challenges doctors face when patients with long COVID symptoms don’t show any clear signs of heart problems.
The researchers are calling for more research to better understand the different forms and causes of long COVID symptoms. This could help identify possible treatments.
Until new treatments become available, exercise training could help those with reduced exercise capacity improve their symptoms.
However, it’s important to consider safety as some people have concerns that exercise might make their symptoms worse.
“Although exercise probably won’t cure long COVID, preliminary data suggests it could improve exercise capacity, symptoms, and quality of life,” said Durstenfeld.
“But we need more research to fully understand the role of exercise in long COVID.”
If you care about COVID, please read studies about new evidence on rare blood clots after COVID-19 vaccination, and how diets could help manage post-COVID syndrome.
For more information about COVID, please see recent studies about eye disease linked to severe COVID-19 in older people, and results showing zinc could help reduce COVID-19 infection risk.
The study was published in The Journal of Infectious Diseases.
Copyright © 2023 Knowridge Science Report. All rights reserved.
