A Systematic Review and Meta-Analysis of Exercise Capacity Assessments in Long COVID Exercise Programs

The aim of this systematic review was to evaluate different exercise capacity measures utilized in long COVID exercise intervention studies and to identify which parameters may be responsive to exercise programs for individuals with long COVID.

The Web of Science, PubMed, Embase, Scopus and CINAHL were searched for cohort studies, clinical trials, and randomized controlled trials  reporting on exercise capacity parameters in long COVID exercise programs up to March 2024. Title, abstracts, and full texts were screened according to predefined eligibility criteria, which included studies that specifically addressed patients with long COVID, reported on exercise capacity outcomes, and incorporated an exercise intervention group in conjunction with a control or usual care group. The methodological quality of the included studies was assessed using the Joanna Briggs Institute (JBI) critical appraisal checklists. Meta-analyses were performed using both fixed and random effects models in RevMan Web.

A total of 11 studies with 750 patients were included in the systematic review, with 6 studies comprising 357 patients included in the meta-analysis. Seventy-three percent of the included studies were rated as high quality, as they met a minimum of 70% of the criteria established in the appraisal checklist. This systematic review identified commonly used exercise capacity parameters in long COVID as forced vital capacity (FVC) (n = 6 studies), forced expiratory volume in one second (FEV₁) (n = 7 studies) and 6-minute walk test distances (6MWD) (n = 7 studies). The meta-analyses revealed a significant mean difference in 6MWD (mean difference: 22.49 meters , 95% CI [6.13, 38.85], p = 0.007) between the exercise and control groups; while no significant differences were observed for FVC, FEV₁, FEV₁ predicted, FEV₁/FVC, and peak VO₂.

Our meta-analyses showed that the most commonly used exercise capacity parameters in long COVID were FVC, FEV₁ and 6MWD. Among these, 6MWD demonstrated the most significant changes in response to the exercise program.

The findings of this study suggest that rehabilitation programs for patients with long COVID could use 6MWD as a primary marker of progress, as it reflects improvements most effectively.