Author(s): NECHALOVÁ, L., BIELIK, V., ŠPANÍK, M., GRENDÁR, M., Institution: FACULTY OF PHYSICAL EDUCATION AND SPORT, COMENIUS UNIVERSITY IN BRATISLAVA, Country: SLOVAKIA, Abstract-ID: 1556

INTRODUCTION:
Declining physical fitness in adolescents has become an increasing public health concern, potentially contributing to the early development of chronic diseases. However, its predictive value for morbidity at the population level remains insufficiently investigated. Therefore, the aim of this study was to assess whether cardiorespiratory fitness and muscular strength are significant predictors of chronic diseases in school-aged children.
METHODS:
Data were obtained from the Slovak Olympic and Sports Committee’s National Physical Fitness Project (OLOV). The study included 90,941 students in Grades 5 to 9 (aged 11–15 years). Cardiorespiratory fitness was assessed using the 20-m shuttle run test and standardized to Z-scores. Muscular strength was quantified as a composite Z-score derived from the bent-arm hang, standing long jump, and 30-s sit-ups. Population-normalized morbidity data on endocrine, mental, respiratory, and circulatory diseases were obtained from the National Health Information Centre of Slovakia (NCZI). Analyses across eight regions were performed using generalized linear mixed-effects models.
RESULTS:
Higher cardiorespiratory fitness and muscular strength were significantly associated with a lower prevalence of endocrine (β = −24.2 and −36.74), mental (β = −62.3 and −59.06), and respiratory diseases (β = −38.07 and −39.76), respectively (all p < 0.001). The strongest associations were observed for mental disorders, with prevalence decreasing by 83.16% per 1 SD increase in cardiorespiratory fitness and by 78.75% per 1 SD increase in muscular strength.
CONCLUSION:
In conclusion, higher physical fitness was significantly associated with lower rates of mental, respiratory, and endocrine morbidity, with the strongest association observed for mental disorders. These findings indicate a potentially important role of physical fitness in psychological well-being during adolescence.
Funding: This study was supported by the Slovak Research and Development Agency under Grant No. VEGA 1/0587/26 and by the national project MŠVVaM-NP E0521-01-2025.