A study including nearly 300 individuals showed that the most common cause of exercise limitation in patients recovered from COVID-19 regardless of disease severity was Peripheral muscle fatigue.

Cardiopulmonary exercise testing (CPET) was performed on 144 persons who had recovered from COVID-19 and 144 matched controls who had not recovered from COVID-19. The participants were 43 years old on average, with 57 percent males. In 60 percent, 21 percent, and 19 percent of the patients, COVID-19 was classified as mild, moderate, or severe, respectively. In 41% of patients, residual symptoms were reported. CPET was conducted 14 weeks following the commencement of the illness. The majority of CPET limits (92%) among COVID-19 patients were due to muscular tiredness; 2% were due to cardiovascular limitations and 6% pulmonary limitations.

Data from the post-COVID CPET showed that the peak oxygen consumption, the first and second ventilatory thresholds (VT1 and VT2), and heart rate were all different in the post-COVID CPET. Lower levels were associated with more severe illnesses and substantial differences between COVID patients and controls. These observations were presented at the European Association of Preventive Cardiologys annual congress. (Medscape Medical News, April 21, 2022)