Effects of different exercise training modalities in post-COVID-19 individuals: a systematic review of randomized controlled trials.

Abstract

Although the COVID-19 pandemic has ended, long-term effects persist. Exercise training (ET) supports recovery, but evidence on optimal modalities is limited. This study evaluated the effects of different ET modalities in post-COVID-19 individuals. A systematic search identified randomized controlled trials (RCTs) up to 23 September 2025, involving adults with COVID-19. Studies compared ≥4-week interventions-aerobic training, high-intensity interval training (HIIT), or combined training (aerobic plus resistance training)-with usual care (UC). Risk of bias and certainty of evidence were assessed using RoB 2.0 and GRADE. Eighteen RCTs (<i>N</i> = 1171) were included. Interventions varied in intensity and duration. Most studies had "some concerns" regarding bias, and overall certainty of evidence was low to very low. Overall, ET modalities were associated with improvements in functional capacity (VO₂peak or six-minute walk distance) and muscle strength, although not all studies showed significant differences vs. UC. HIIT demonstrated the greatest VO₂peak gain (mean difference: 6.17 ml.kg^-1.min^-1). Effects on quality of life, anxiety, and depression were inconsistent. Most cardiopulmonary parameters (VE/VCO₂ slope, OUES) showed no significant changes, with mixed results for O₂ pulse and ventilation. Despite heterogeneous protocols and low certainty of evidence, structured ET appears beneficial for post-COVID-19 recovery. Multiple ET approaches may be effective rather than a single "optimal" approach.