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Adults with persistent cases of long COVID lost some of their ability to exercise 3 months after getting COVID, according to a new study published in JAMA Network Open.
Researchers from the University of California San Francisco and Zuckerberg San Francisco General Hospital identified 38 previous studies that used cardiopulmonary exercise testing (CPET) to measure how well people with long COVID could exercise after recovering from COVID. CPET measured how much oxygen they used as they exercised on either a stationary bike or a treadmill to find out how well their heart and lungs were working.
Someone who used to play doubles tennis, for example, may find that they need to transition to a lower-impact sport like golf if they have long COVID symptoms, lead author and UCSF cardiologist Matthew Durstenfeld, MD, said in a news release.
“But it’s important to note that this is an average,” he said. “Some individuals experience a profound decrease in energy capacity and many others experience no decrease.”
The team narrowed down their sample from 38 studies to 9, comparing exercise testing results from 359 people who recovered from COVID to that of 464 people who had symptoms consistent with long COVID. The age range of the people studied was 39 to 56 years old.
While the authors say they have some reservations about the results from their meta-analysis – mainly due to the studies’ small sample sizes, oversampling of COVID patients who were hospitalized, and varying definitions of long COVID – their findings still “provided evidence of a clinically significant, mild to moderate decrease in exercise capacity among individuals with [long COVID] compared with infected individuals without symptoms despite different definitions of [long COVID],” they wrote.
Losing some ability to exercise because of long COVID symptoms isn’t new information, but understanding the role of CPET results in long COVID patients may be a powerful measuring tool.
Among the study’s limits, the researchers noted, was that their search plan was not peer-reviewed and the studies included in the analysis were not limited solely to peer-reviewed papers. Selection bias – that so many people in the study had been evaluated after recovering from severe COVID infections – also made it difficult to get a clear picture of how common reduced exercise capacity is.
“Further research should include long-term observational assessments to understand the trajectory of exercise capacity,” says author Priscilla Hsue, MD. “Trials of potential therapies are urgently needed, including studies of rehabilitation to address deconditioning, as well as further investigation into dysfunctional breathing, damage to the nerves that control automatic body functions and the inability to increase the heart rate adequately during exercise.”
JAMA Network Open: “Use of Cardiopulmonary Exercise Testing to Evaluate Long Covid-19 Symptoms in Adults.”