Digital natives: Social media, physical activity and BMI in Zagreb adolescents

Abstract

Background: Today's adolescents are immersed in a digital environment, with social networks central to their lives for entertainment, communication and getting information. Being online enables adolescents to share their daily experiences, opinions, emotions, attitudes and express their identity. Still, the displacement hypothesis suggests that time spent on media reduces the time available for other, offline activities (e.g., physical activity), leading to potential negative impact on health.

Objective: To determine which social networks adolescents use most often, how often and what is their main motivation for using these networks. Furthermore, to examine whether the frequency of using social networks is the same among respondents who practice physical activity 3 or more times a week compared to respondents who are not so physically active. Also, to determine whether the body mass index differs between respondents who use the internet at all or very rarely and those who use it more frequently.

Subjects and methods: This research, part of the Institute for Anthropological Research project IA-INT-2024-BiCePs_Nutrition, surveyed 500 high school students in Zagreb, Croatia, who voluntarily participated. The students independently filled out a questionnaire on demography, physical activity, frequency and motivation for using social networks. The data was analysed using SPSS software.

Results: Analyses have shown that Instagram and TikTok are used more often than Facebook and/or X. For communication, students most often use Snapchat and WhatsApp. Most students access these networks several times a day. The students self-assessed that the use of social networks has an influence on their thoughts, feelings and self-perception. The association between social media time and physical activity level was generally weak, just as with BMI.

Conclusion: To conclude, the prevalence of social media use among adolescents in Croatia is high, just as in general in the world. Still, this bad habit has not yet affected their physical activity level that much, nor their BMI.