Introduction: Nowadays, studying the features of influence of mobile devices on stereotypes of children’s behavior and communication between children and adults acquires special significance. In modern conditions, a child loses the need for verbal communication and physical activity devoting almost all leisure time to virtual space. As a result, along with the development of specific features of cognitive functions in children their physical activity reduces significantly posing health risks and contributing to excess body weight, obesity, diseases of cardiovascular and nervous systems. Our objective was to evaluate the effectiveness of restrictions imposed on the use of cellphones at schools. Materials and methods: The study was conducted in Novosibirsk in January – March 2020. It involved 454 school children including 228 children who did not use cellphones during school breaks (observation group) and 226 children who actively used cellphones during breaks and lessons (control group). Results: The observation group was characterized by significantly higher energy expenditures related to physical activities with a dynamic component during breaks (p≤0.05) as confirmed by objective data collected by a Polar V800 pulsometer with Polar H10 heart rate sensors, a higher percentage of verbal communications (81.2% against 21.2%), a lower prevalence of posture disorders as detected by computer topography (32.8% against 65.8%) and signs of overexertion of the visual apparatus during the school day among the children having functional visual loss (34.6% against 69.2%). Conclusions: The results prove the effectiveness of restrictions imposed on the children’s use of cellphones at school.