The results of a comprehensive assessment of the impact on the functional state of an organ-ism at 225 students 12-13 years of use in training activities tablets, laptops compared to desktop computers. A 717 measurement indicators of environmental factors stay. Estimated working posture in 186 students working with a laptop and a tablet and proved the formation of their forced "front" working posture. Proved the greatest negative impact on the body of children reading and typing on the tablet compared to the laptop. First identified sex differences in the formation of mental fatigue when reading text on the screen for girls and for boys set texts. Developed hygienic requirements of sanitary norms and chart-selection algorithm portable equipment for schools.