Maximal oxygen uptake, pulmonary function and walking economy are not impaired in patients diagnosed with long COVID

Introduction: SARS-CoV-2 may result in the development of new symptoms, known as long COVID, a few months after the original infection.

Purpose: It is elusive to what extent physical capacity in patients diagnosed with long COVID is impacted.

Methods: We compared maximal oxygen uptake (V̇O_2max), one of the single most important factors for cardiovascular health and mortality, expired lung volumes and air flow, oxygen cost of walking and 6-min-walking-test (6MWT), in 20 patients diagnosed with long COVID (11 males and 9 females; 44 ± 16 years (SD); 26.7 ± 3.8BMI, duration of acute phase 1.7 ± 1.2 weeks, tested 4 ± 3 months after long COVID diagnosis) with 20 healthy age and sex matched controls (11 males and 9 females; 44 ± 16 years; 25.9 ± 4.0BMI).

Results: Long COVID patients had a V̇O_2max of 41.4 ± 16.2 mL∙kg^-1∙min^-1(men) and 38.2 ± 7.5 (women) and this was not different from controls. Similarly, mean spirometry measures in the patient group (VC; FVC; FEV₁; FEV₁/FVC) were also not different (85-106%) from predicted healthy values. Finally, inclined treadmill (5%, 4 km∙h^-1) walking economy was not different between the groups (long COVID: 15.2 ± 1.1 mL∙kg^-1∙min^-1; controls: 15.2 ± 1.2 mL∙kg^-1∙min^-1), while the 6MWT revealed a difference (long COVID: 606 ± 118 m; controls: 685 ± 85 m; p = 0.036).

Conclusion: V̇O_2max, oxygen cost of walking, and spirometry measurements did not appear to be impaired in patients diagnosed with long COVID with a prior mild to moderate SARS-CoV-2 infection. The typical outcomes in these essential factors for health and longevity implies that while long COVID can present with a range of symptoms, caution should be made when attributing these symptoms directly to compromised pulmonary function or V̇O_2max.