Objectives: This study aims to investigate the relationship between physical activity, body mass index and health complaints among Hungarian school-aged children.

Methods: The survey was in January 2020 in Hungary. The sample consisted of 857 children and adolescents (399 males and 458 females) aged 7-20 years (12,61±3,57). The tool of our study was InBody770 examination of body mass index (BMI), physical activity questionnaire for older children (PAQ-C) and adolescents (PAQ-A) examination of physical activity (PA) and health behaviour in school-aged children (HBSC) examination of health complaints. We used IBM SPSS Statistics 24.0 version and the significance level was set at P<0,05.

Results: The Mann-Whitney test was used to assess differences between gender in PA level, there was a significant difference (U=76371; Z=-4,315; P=0,00) between boys (M=3,09; SD=1,045) and girls (M=2,78; SD=1,021) PA level. 67,4% of the participants had a normal weight, while 10,3% of them were overweight, 6,5% of them were underweight and 15,8% of them were obese. In weight status categories was no significant difference (P=0,081) between genders. Based on age children’s BMI (18,3±3,83) was significantly lower (Z=-13,035; p<0,001) than adolescents (21,9±4,23). We found significant difference (χ²=21,504; P=0,049) between PA and BMI categories. The prevalence of having headaches (χ²=; P<0,001), feeling low (χ²=31,431; P<0,001), irritable (χ²=27,542; P<0,001) and being nervous (χ²=5,586; P=0,018) was significantly higher among girls. We found significant difference between PA and feeling low (χ²=31,81; p=0,01), being irritable (χ²=31,88; p=0,01).

Conclusions: Our study and international literature show that children with normal BMI have high PA. The PA seems to have positive effect on BMI and protective effect against health complaints in childhood.