The problem of preservation and maintenance of secondary school pupils` intellectual work capacity by means of physical education is still not enough studied (for example, its dynamics in time is unknown). The research objective it to study pupils` intellectual work capacity on application of additional daily sports and improving program. As a research method, an experiment was conducted in 5th grade of school throughout three academic terms (September to April). Within the experimental group, the classes in physical education were supplemented by the additional daily sports and improving program. Within the control group, only classes in physical education were conducted. The level of intellectual work capacity was assessed by “Proof test” technique (distinctions are significant a level p<0,01 on Student`s criterion). Within the control groups, high intellectual work capacity after lessons was recorded only in the second academic term. By the end of academic year, it considerably reduced which conforms to generally accepted ideas of accumulation of pupils` fatigue by the time and decrease in full value of cognitive functions, particularly, of attention properties. Within the experimental groups, at the same time, pupils` intellectual work capacity was stably growing during three academic terms. Thus, the increase in daily physical activity has a positive effect on the preservation of pupils` intellectual work capacity during academic year as well as prevention and exhaustion - to its end. The dynamics of these pupils` intellectual work capacity is stable during the whole academic year and has a tendency to increase in the work content and quality in comparison with similar indicators of pupils having a usual motional activity. In organizing the educational process, teachers should take into account the decrease in intellectual work capacity of pupils both with usual and extended motional activity that is observed in the middle of school week.