Maggio ABR; University Hospitals of Geneva, Geneva, Switzerland,
Perret I; Alramadina N; Perrin A; Barazzone C; Mornand A

Pulmonary Medicine. 2026(1):e5599011, 2026.

BACKGROUND: Post-COVID syndrome (PCS) in adolescents, marked by persistent
symptoms such as dyspnea and fatigue, remains poorly understood,
particularly in those referred for exercise intolerance.

OBJECTIVE: The objective of this study is to describe the clinical
presentation and cardiorespiratory fitness (CRF) of adolescents with PCS
and identify factors distinguishing those with normal versus reduced CRF.

STUDY DESIGN: In this cross-sectional study, 31 adolescents (90% female)
with PCS underwent cardiopulmonary exercise testing (CPET), pulmonary
function tests, and completed validated questionnaires assessing fatigue,
depression, hyperventilation, physical activity, and quality of life
(QoL). Patients were grouped by CRF status and compared.

RESULTS: Symptoms were more prevalent than in general PCS literature,
likely due to referral bias. Moderate depression risk was present in 35%,
and 75% reported QoL impairment comparable with chronic conditions. Nearly
half (48%) had reduced CRF. CRF was not associated with acute infection
severity but correlated with orthostatism, reduced O2 pulse, and increased
static air trapping (p < 0.05). Preinfection physical activity was
positively associated with CRF (p = 0.014), whereas postinfection activity
levels were similar across groups.

CONCLUSION: PCS significantly impacts CRF, QoL, and psychological
well-being in adolescents with exercise intolerance. Reduced CRF appears
multifactorial, involving autonomic dysfunction, pulmonary limitations,
and deconditioning. These findings underscore the need for comprehensive
evaluation and targeted management strategies in this vulnerable
population.