Stenberg H; Department of Clinical Sciences Lund, Lund University, Sweden.
Tufvesson E; Mosen H; Skarping I

Scandinavian Journal of Primary Health Care. 44(1):2623877, 2026 Dec.

BACKGROUND: Post COVID-19 condition remains a complex and challenging
issue, with diverse manifestations, despite accumulating research and
clinical experience. Dyspnea is one of the most common symptoms reported
in post COVID-19 condition. Cardiopulmonary exercise testing (CPET) offers
a cohesive assessment of dyspnea and exercise limitations. The Nijmegen
questionnaire is a form for assessment of dysfunctional breathing.

AIM: The aim was to explore relationships between self-reported post
COVID-19 respiratory symptoms, assessed by Nijmegen questionnaire, and the
results of a 6-minute walk test (6MWT) and CPET, in patients with mild
primary infection of COVID-19, managed within primary healthcare.

METHODS: A total of 15 participants with long-term dyspnea after a mild
COVID-19 infection were prospectively included at primary healthcare
facilities between July 2021 and April 2022. At inclusion, all subjects
performed a 6MWT and answered the Nijmegen questionnaire. All subjects
underwent CPET within 4 months of study inclusion. We estimated
correlations between Nijmegen score (both total score and a subset of the
questionnaire focusing on respiratory symptoms), and the 6MWT and CPET
derived variables, respectively.

RESULTS: Nijmegen scores (both total and particularly a respiratory
subset) were inversely correlated to 6MWT walking distance, but not to
spirometric parameters. Subjects with more self-reported symptoms had
higher end-tidal O2 and lower end-tidal CO2, indicating mild
hyperventilation. Nijmegen scores also correlated with CPET variables
reflecting breathing pattern.

CONCLUSIONS: Nijmegen score was associated with CPET variables and
walking distance at 6MWT. Post COVID-19 condition could be associated with
mild hyperventilation, also in subjects without overt dysfunctional
breathing pattern.