By Social Links for Adriana Diaz Published Feb. 16, 2024,

Extreme fatigue and difficulty exercising are common symptoms of long COVID — now scientists may finally have discovered why.

While most people who test positive for the coronavirus are over their symptoms within a week or two, more research is showing that some people continue to report symptoms — and even develop new ones — three months after their initial positive test, lasting for months or even years.

A new study, published in the journal Nature Communications, suggests that some of these symptoms may persist or worsen as those with long COVID-19 experience biological changes in their bodies after working out — most notably involving their muscles.

“We’re seeing clear changes in the muscles in these patients,” Michèle van Vugt, professor of internal medicine at Amsterdam UMC, said in a statement.

The study found that long COVID patients had extreme fatigue, changes in muscle composition and widespread muscle damage.