Maximal oxygen uptake, pulmonary function and walking economy are not impaired in patients diagnosed with long COVID, 2024, Berg et al

[forestglip]

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

OK Berg, N Aagård, J Helgerud, MF Brobakken, J Hoff, E Wang

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 (V̇O2max), 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 V̇O2max 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
V̇O2max, 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 V̇O2max.

Link | PDF (European Journal of Applied Physiology) [Open Access]

 

[Snow Leopard]

Caution should be made when attributing these symptoms directly to compromised pulmonary function or V̇O2max.

We knew that in January 2020.

Put alternatively however, it can also be said that the symptoms of these patients are also not due to deconditioning.

As for the rest, the total lack of discussion of 2 day CPETs suggests these researchers either don't know much about ME/CFS research (nor the exercise physiology of fatigubility), or they don't care.

 

[forestglip]

A response has been posted to this paper:

No impairment of maximal oxygen uptake in patients diagnosed with long COVID?

René Garbsch, Frank C. Mooren & Boris Schmitz

Data from our group (Garbsch et al. 2024), and findings from earlier studies in the field (Ostrowska et al. 2023) consistently demonstrate significant impairments in cardiopulmonary fitness and physical performance among patients with long-term sequale after SARS-CoV-2 infection.

Of note, the center itself correctly states on its homepage that many post-COVID patients report difficulty participating in daily activities as before and many describe worse physical function in the form of reduced endurance and muscle strength after prolonged periods of inactivity (https://treningsklinikken.no). It appears that precisely these patients were not included in the present study, which already only involved a relatively small number of cases (n = 20, lead symptoms including fatigue [n = 19], dyspnea [n = 9], and palpitations/ chest pain [n = 9]) and can thus not be considered representative.

Of note, patients also exhibited unusually high 6-min walking performance at 606 ± 118 m compared to recent studies with 352 ± 75 m (Doehner et al. 2024). The description of physical activity levels suggests a population used to regular exercise training, corresponding to the finding that their performance level after the infection still reaches about 100% of the predicted value.

Regretfully, the title chosen by the authors indicates that exercise impairment is not a lead symptom of long COVID in general. We feel that this lack of accuracy does not reflect the considerable disease burden of many long/post-COVID patients which is often followed by significant, diverse psychosocial challenges.

Link | PDF