Risk of frequent morbidity, self-reported health status and frequent use of medicines for headache and nervous strain was 1.5-1.7 times higher to those who exercise sometimes or never compared to those who exercise 2-3 and more times per week. School surroundings are not quite healthy and comfortable for Lithuanian students. Two thirds of students (67,0%) evaluated possibility to exercise during brakes as bad. The possibility to use to advantage the brakes when there are no lessons during the day at school (the "windows") was evaluated positively only by one fifth part of the respondents. The study showed that the information on some health topics students are getting at school is not sufficient. Every fifth respondent evaluated their information on physical activity and hardening as insufficient. One third part of them feels lack of information on headwork hygiene, stress management and doping influence on health.

Optimal physical activity was more characteristic for the students whose mother’s education is higher (43,2%) compared to the coevals with lower maternal education (33,5%), χ 2 =11,19, p=0,011. This difference is significant for the students, who live in the city. Students whose homework’s doing duration does not exceed the limit of 13 hours during the week, as it is recommended in the hygienic regulations, characterize optimal physical activity (66,1%) more often compared to those who prepare homework longer (53,7%), χ 2 =15,68, p=0,0001. Insufficient physical activity was more prevalent among those students who considered their ability to move actively at school as poor or insufficient (94,2%) compared to those, who evaluated this possibility as good (90,6%), χ 2 =4,6, p=0,032; to 12-formers these possibilities are more important than for 11 – formers. Among the students who indicated they lack the ability to schedule work and leisure time 52,1% of the respondents were characterized to have insufficient physical activity and 40,5% optimal physical activity, χ 2 =13,38, p=0,0001. This evidence is especially important among the girls and residents of the cities. Conclusion. Mother’s higher education, optimal duration of homework, favourable possibilities to move actively during the brakes at school, student’s ability to schedule work and leisure time are important in ensuring optimal physical activity among the 11-12 form students.