Korean J Sports Med.  2025 Mar;43(1):1-12. 10.5763/kjsm.2025.43.1.1.

Effects of Combined Exercise Training on Symptoms and Physical Fitness in Young Adults with Mild Long COVID

• Choi TG
• Kim JY
• Min HJ
• Kim HJ
• Bunsawat K
• Kunutsor SK
• Heffernan KS
• Jae SY

• KMID: 2565710
• DOI: http://doi.org/10.5763/kjsm.2025.43.1.1

Abstract

Purpose
The aim of this study was to examine whether a combined exercise (EX), including aerobic, resistance, and inspiratory muscle training, reduces fatigue and dyspnea, improves physical fitness, and if increased physical fitness after exercise is associated with attenuating symptoms in young adults with mild long coronavirus disease (COVID) symptoms.
Methods
Twenty-eight young adults (aged 23±4 years) with long COVID were randomly assigned to either the EX group (n=14), which underwent aerobic, resistance, and inspiratory muscle training three times per week for 8 weeks, or the control (CON) group (n=14). Symptoms of dyspnea and fatigue were assessed using self-report questionnaires. Cardiorespiratory fitness was directly measured during cardiopulmonary exercise testing, while muscle strength was measured by isokinetic muscle testing. These variables were measured before and after the exercise intervention.
Results
Compared to the CON group, the EX group showed improvements in symptoms of fatigue and dyspnea, maximal oxygen consumption (VO_2peak ), and peak torque, with significant interaction effects observed (p＜ 0.05). The EX group exhibited a mean difference of 2.9 mL/kg/min in VO_2peak (95% confidence interval [CI], 1.8−4.0) and 13.0 Nm (95% CI, 6.1−19.8) in peak torque compared to the CON group (p＜0.05). Improvements in VO_2peak were negatively associated with attenuations in both fatigue and dyspnea after the exercise intervention (p＜0.05).
Conclusion
These findings indicate that EX training can effectively alleviate symptoms and improve physical fitness in young adults with mild long COVID. Structured exercise training may serve as an effective intervention to improve the health of those with long COVID.

Keyword

Post-acute COVID-19 syndrome; Exercise; Cardiorespiratory fitness; Muscle strength

Figure

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  Fig. 1 Experimental design.

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  Fig. 2 Correlation between changes in cardiorespiratory fitness, muscle strength, and long COVID symptoms. (A) Maximal oxygen consumption vs. fatigue severity scale. (B) Maximal oxygen consumption vs. mMRC score. (C) Peak torque (extension) vs. fatigue severity scale. (D) Peak torque (extension) vs. mMRC score. EX: exercise group, CON: control group, mMRC: modified Medical Research Council.

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