Comparisons between anosmia and ageusia with neurological symptoms and cardiorespiratory fitness among post-COVID-19 individuals: a cross-sectional study

BACKGROUND: Anosmia and ageusia are among the most frequent symptoms of post-COVID-19 syndrome, yet their association with neurological symptoms and cardiorespiratory fitness remains unclear. OBJECTIVE: To compare the presence of anosmia and ageusia with neurological symptoms and cardiorespiratory fitness in post-COVID-19 individuals. METHODS: This cross-sectional study included 201 post-COVID-19 individuals who completed a standardized questionnaire assessing anosmia, ageusia, and neurological symptoms. Cardiorespiratory fitness was assessed using the Bruce treadmill test with direct measurement of peak oxygen uptake (VO₂peak). Missing data were handled by multiple imputation. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using binary logistic regression, adjusted for age, sex, acute infection severity, medical history, body fat percentage, and skeletal muscle mass. RESULTS: After adjustment, anosmia was independently associated with dizziness (OR = 2.22; 95% CI 1.15-4.31) and aural fullness (OR = 4.54; 95% CI 1.16-17.80), and ageusia with memory deficit (OR = 2.91; 95% CI 1.47-5.75) and aural fullness (OR = 4.08; 95% CI 1.02-16.30). No significant associations were found with tinnitus or hearing loss. VO₂peak did not differ significantly between participants with and without anosmia (mean difference 1.13 mL/kg/min; Cohen's d = 0.14; 95% CI - 0.14 to 0.42; p = 0.325) or ageusia (mean difference 1.36 mL/kg/min; Cohen's d = 0.17; 95% CI - 0.12 to 0.45; p = 0.244). CONCLUSIONS: Anosmia and ageusia are associated with neurological symptoms but not with cardiorespiratory fitness in post-COVID-19 individuals, suggesting partially independent phenotypes. These symptoms should be considered in therapeutic assessment and management.