Impact of Post-COVID Syndrome on Cardiorespiratory Fitness, Psychological Well-Being, and Quality of Life in Adolescents: A Cross-Sectional Study.

Nearly half of adolescents with post-COVID syndrome referred for exercise intolerance had reduced cardiorespiratory fitness.

• 48% of the 31 adolescents in the study had reduced CRF as measured by cardiopulmonary exercise testing (CPET)
• The study population was 90% female
• Patients were grouped by CRF status (normal versus reduced) and compared
• The high symptom prevalence was attributed to referral bias, as patients were referred specifically for exercise intolerance

Reduced CRF was associated with orthostatism, reduced O₂ pulse, and increased static air trapping.

• All three factors — orthostatism, reduced O₂ pulse, and increased static air trapping — were statistically significant at p < 0.05
• These associations suggest autonomic dysfunction, cardiovascular limitations, and pulmonary limitations as contributing mechanisms
• CRF was not associated with acute infection severity
• The findings suggest reduced CRF is multifactorial in origin

Preinfection physical activity level was positively associated with cardiorespiratory fitness in adolescents with post-COVID syndrome.

• Preinfection physical activity was positively associated with CRF at p = 0.014
• Postinfection activity levels were similar across CRF groups, suggesting deconditioning as a contributing factor
• Physical activity was assessed using a validated questionnaire

A substantial proportion of adolescents with post-COVID syndrome showed moderate depression risk and quality of life impairment.

• Moderate depression risk was present in 35% of the 31 adolescents
• 75% reported quality of life impairment comparable with chronic conditions
• Depression and QoL were assessed using validated questionnaires
• Fatigue, hyperventilation, and physical activity were also assessed with validated tools

Post-COVID syndrome in adolescents referred for exercise intolerance presented with symptom prevalence higher than reported in the general post-COVID literature.

• Persistent symptoms included dyspnea and fatigue
• The study authors attributed the higher symptom prevalence to referral bias
• The cohort consisted of 31 adolescents who all underwent CPET, pulmonary function tests, and validated questionnaires
• The study design was cross-sectional